Consolidated Sponsored Investment Portfolios [Abstract] Consolidated Sponsored Investment Portfolios [Abstract] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Consolidated T. Rowe Price investment products [Member] Consolidated Investment Portfolios [Member] Consolidated Investment Portfolios [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair value, measurements, recurring [Member] Fair Value, Measurements, Recurring [Member] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Equity securities [Member] Equity Securities [Member] Fixed income securities [Member] Fixed Income Investments [Member] Other investments [Member] Other than Securities Investment [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Investments Investments, Fair Value Disclosure Total Assets, Fair Value Disclosure Liabilities Financial and Nonfinancial Liabilities, Fair Value Disclosure Fair Value Disclosures [Abstract] Fair value measured at NAV [Member] Fair Value Measured at Net Asset Value Per Share [Member] Cash equivalents held in T. Rowe Price money market funds T. Rowe Price investment products Equity Securities, FV-NI Investments, Debt and Equity Securities [Abstract] Investment [Table] Investment [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] T. Rowe Price investment products [Member] Sponsored Investment Portfolios [Member] Sponsored Investment Portfolios [Member] T. Rowe Price investment products designated as economic hedge of supplemental savings plan liability [Member] Sponsored Investment Portfolios Designated As Economic Hedge Of Supplemental Savings Plan Liability [Member] Sponsored Investment Portfolios Designated As Economic Hedge Of Supplemental Savings Plan Liability [Member] Investment partnerships and other investments [Member] Investment Partnership and Other Investments [Member] Investment Partnership and Other Investments [Member] Interest in UTI Asset Management Company Limited (India) [Member] UTI Asset Management Company India [Member] UTI Asset Management Company India [Member] Investment partnerships and other investments [Member] Other Equity Method Investments [Member] Other equity method investments Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Assets [Member] Assets [Member] Liability [Member] Liability [Member] Redeemable noncontrolling interest [Member] Redeemable Noncontrolling Interest [Member] The line item on the balance sheet representing the aggregate carrying amount of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity. Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of accumulated other comprehensive income [Member] Reclassification out of Accumulated Other Comprehensive Income [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Currency translation adjustments [Member] Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Investment [Line Items] Investment [Line Items] Investments held at fair value Equity method investments Equity Method Investments U.S. Treasury note Debt Securities, Held-to-maturity Total Investments Equity method investment (ownership percentage) Equity Method Investment, Ownership Percentage Net unrealized gains (losses) on T. Rowe Price investments product recognized in nonoperating income Equity Securities, FV-NI, Unrealized Gain (Loss) Net increase (decrease) in assets, liabilities, and redeemable noncontrolling interest Deconsolidation Value2 Represents the carrying value of the assets (liabilities or redeemable noncontrolling interest) deconsolidated during the period as valued on the date that the parent no longer had a controlling financial interest in the subsidiary. Gains recognized upon deconsolidation Nonoperating Income (Expense) Earnings Per Share [Abstract] EARNINGS PER SHARE CALCULATIONS Earnings Per Share [Text Block] Statement of Cash Flows [Abstract] Statement [Table] Statement [Table] Statement [Line Items] Statement [Line Items] Cash and cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value, Including Consolidated Sponsored Investment Portfolios Cash and Cash Equivalents, at Carrying Value, Including Consolidated Sponsored Investment Portfolios Cash and cash equivalents at end of period Disclosure of Compensation Related Costs, Share-based Payments [Abstract] STOCK-BASED COMPENSATION Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Rollforward of stock options Share-based Compensation, Stock Options, Activity [Table Text Block] Rollforward of nonvested restricted shares and restricted stock units Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Future stock-based compensation expense Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted shares [Member] Restricted Stock [Member] Restricted stock units [Member] Restricted Stock Units (RSUs) [Member] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Time-based [Member] Share-based Compensation Award, Tranche One [Member] Performance-based [Member] Share-based Compensation Award, Tranche Two [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Nonvested at December 31, 2018 (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Grants (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Nonvested at March 31, 2019 (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Weighted-average fair value of nonvested restricted shares and restricted stock units at December 31, 2018 (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Weighted-average fair value of restricted shares and restricted stock units granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Weighted-average fair value of restricted shares and restricted stock units vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Weighted-average fair value of restricted shares and restricted stock units forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Weighted-average fair value of nonvested restricted shares and restricted stock units at March 31, 2019 (in dollars per share) Nonvested shares where performance threshold has been met (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Performance Threshold Met, Number Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Performance Threshold Met, Number Stockholders' Equity Note [Abstract] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Total accumulated other comprehensive income (loss) [Member] AOCI Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Net deferred tax benefits (income taxes) on other comprehensive income (loss) before reclassifications Other Comprehensive Income (Loss) before Reclassifications, Tax Net deferred tax benefits (income taxes) on reclassifications from AOCI Reclassification from AOCI, Current Period, Tax Total net deferred tax benefits (income taxes) Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Statement of Stockholders' Equity [Abstract] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting standards update 2016-01 [Member] Accounting Standards Update 2016-01 [Member] Accounting standards update 2018-02, currency translation adjustments [Member] Accounting Standards Update 2018-02, Currency Translation Adjustments [Member] Accounting Standards Update 2018-02, Currency Translation Adjustments [Member] Statement, Equity Components [Axis] Common stock [Member] Common Stock [Member] Additional capital in excess of par value [Member] Additional Paid-in Capital [Member] Retained earnings [Member] Retained Earnings, Unappropriated [Member] Accumulated other comprehensive income (loss) [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Balances (in shares) Shares, Outstanding Beginning Balance Stockholders' Equity Attributable to Parent Cumulative effect adjustment upon adoption of new accounting guidance on January 1, 2018 Cumulative Effect of New Accounting Principle in Period of Adoption Balances, As Adjusted Stockholders' Equity Attributable to Parent, Adjusted Balance Amount of stockholders' equity attributable to parent, after the cumulative effect adjustment of a new accounting principle applied in the period of adoption. Net income Net Income (Loss) Attributable to Parent Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Dividends declared Dividends, Cash Common stock-based compensation plans activity Stock Issued or Granted During Period, Share-based Compensation [Abstract] Shares issued upon option exercises (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Shares issued upon option exercises Stock Issued During Period, Value, Stock Options Exercised Net shares issued upon vesting of restricted stock units (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Gross Net shares issued upon vesting of restricted stock units Adjustments Related to Tax Withholding for Share-based Compensation Forfeiture of restricted awards (shares) Stock Issued During Period, Shares, Restricted Stock Award, Forfeited Forfeiture of restricted awards Stock Issued During Period, Value, Restricted Stock Award, Forfeitures Stock-based compensation expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Restricted stock units issued as dividend equivalents Dividends, Share-based Compensation, Paid-in-kind Common shares repurchased (shares) Stock Repurchased During Period, Shares Common shares repurchased Stock Repurchased During Period, Value Balances (in shares) Ending Balance Increase (Decrease) in Temporary Equity [Roll Forward] Increase (Decrease) in Temporary Equity [Roll Forward] Beginning balances attributable to redeemable non-controlling interests Redeemable Noncontrolling Interest, Equity, Carrying Amount Net income (loss) attributable to redeemable non-controlling interests Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Other comprehensive income (loss), net of tax, attributable to redeemable non-controlling interests Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest Net subscriptions into consolidated T. Rowe Price investment products Subscription From Redemption Distribution To Noncontrolling Interest A positive value represents subscriptions net of redemptions and distributions to redeemable non-controlling interest holders of a less than wholly owned subsidiary. A negative value represents redemptions and distributions paid to redeemable non-controlling interest holders net of subscriptions received. Net reconsolidations of T. Rowe Price investment products Noncontrolling Interest, Increase (Decrease) From Reconsolidation (Deconsolidation) Noncontrolling Interest, Increase (Decrease) From Reconsolidation (Deconsolidation) Ending balances attributable to redeemable non-controlling interests Statement of Comprehensive Income [Abstract] Variable interest entities [Member] Variable Interest Entity, Primary Beneficiary [Member] Equity method investments [Member] Equity Method Investee [Member] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Other comprehensive income (loss) Other Comprehensive Income (Loss), before Tax [Abstract] Consolidated T. Rowe Price investment products - variable interest entities Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax Reclassification gains recognized in non-operating income upon deconsolidation of certain T. Rowe Price investment products Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax Currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax Other comprehensive income (loss) before income taxes Other Comprehensive Income (Loss), before Tax Net deferred tax benefits (income taxes) Other Comprehensive Income (Loss), Tax Total other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Total comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Less: comprehensive income (loss) attributable to redeemable non-controlling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Total comprehensive income attributable to T. Rowe Price Group Comprehensive Income (Loss), Net of Tax, Attributable to Parent Information about Receivables, Revenues, and Services [Abstract] Information about Receivables, Revenues, and Services INFORMATION ABOUT RECEIVABLES, REVENUES, AND SERVICES Information About Receivables Revenues And Services Text Block This element is used to indicate facts reported for the continuing operations of a business entity including disclosure of receivables from sponsored mutual funds for both advisory fees and administrative services provided. This element also includes disclosure of the components of investment advisory fees and administrative fees earned as well as the components of average assets and period end assets under management. Leases [Abstract] LEASES Lessee, Operating Leases [Text Block] CONSOLIDATED T. ROWE PRICE INVESTMENT PRODUCTS Consolidated Sponsored Investment Portfolios [Text Block] Consolidated Sponsored Investment Portfolios [Text Block] Revenue and Services [Table] Revenue and Services [Table] Summarization of information required and determined to be disclosed concerning advisory service revenues and the assets from which those revenues are derived, by customer and investment mandate. Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Investment advisory fees [Member] Asset Management [Member] Administrative service [Member] Administrative Service [Member] Distribution and servicing fees [Member] Distribution Service [Member] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] U.S. mutual funds [Member] Sponsored Mutual Funds In U S [Member] Sponsored mutual funds in the U.S. Subadvised and separate accounts and other investment products [Member] Subadvised, Separate Accounts, And Other Investment Products [Member] Subadvised, Separate Accounts, And Other Investment Products [Member] Other [Member] Other Clients [Member] Other Clients [Member] Equity and blended asset [Member] Stock And Blended Asset [Member] Stock and blended asset [Member] Fixed income, including money market [Member] Bond And Money Market [Member] Bond and money market [Member] Revenue and Services [Line Items] Revenues and Services [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Net revenues Revenue from Contract with Customer, Excluding Assessed Tax Average assets under management Assets under Management, Average Balance Period end assets under management Assets under Management, Carrying Amount OTHER COMPREHENSIVE INCOME AND ACCUMULATED OTHER COMPREHENSIVE INCOME Comprehensive Income (Loss) Note [Text Block] Net income attributable to T. Rowe Price Group Less: net income allocated to outstanding restricted stock and stock unit holders (basic) Participating Securities, Distributed and Undistributed Earnings (Loss), Basic Less: net income allocated to outstanding restricted stock and stock unit holders (diluted) Participating Securities, Distributed and Undistributed Earnings (Loss), Diluted Net income allocated to common stockholders (basic) Net Income (Loss) Available to Common Stockholders, Basic Net income allocated to common stockholders (diluted) Net Income (Loss) Available to Common Stockholders, Diluted Weighted-average common shares Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Outstanding assuming dilution (in shares) Weighted Average Number of Shares Outstanding, Diluted Impact of the components of other comprehensive income (loss) on deferred tax benefits (income taxes) Comprehensive Income (Loss) [Table Text Block] Changes in accumulated other comprehensive income Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Second quarter 2019 Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost To Be Recognized Quarter Two Of Fiscal Year Unrecognized cost of unvested share-based compensation awards to be recognized in quarter two of the fiscal year. Third quarter 2019 Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost To Be Recognized Quarter Three Of Fiscal Year Unrecognized cost of unvested share-based compensation awards to be recognized in quarter three of the fiscal year. Fourth quarter 2019 Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost To Be Recognized Quarter Four Of Fiscal Year Unrecognized cost of unvested share-based compensation awards to be recognized in quarter four of the fiscal year. 2020 Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost To Be Recognized Next Fiscal Year Unrecognized cost of unvested share-based compensation awards to be recognized in the next fiscal year. 2021 through 2024 Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost To Be Recognized From Second Fiscal Year to Vesting Unrecognized cost of unvested share-based compensation awards to be recognized in the second fiscal year through vesting period. Total Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Organization, Consolidation and Presentation of Financial Statements [Abstract] THE COMPANY AND BASIS OF PREPARATION Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Unsettled common stock repurchases liability Unsettled Common Stock Repurchases Liabilities Unsettled Common Stock Repurchases Liabilities Fair value measurements summary Fair Value, Assets Measured on Recurring Basis [Table Text Block] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Variable interest entity, not primary beneficiary [Member] Variable Interest Entity, Not Primary Beneficiary [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Investment carrying values Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Investment Carrying Values, Amount Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Investment Carrying Values, Amount Unfunded capital commitments Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Unfunded Capital Commitments, Amount Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Unfunded Capital Commitments, Amount Uncollected investment advisory and administrative fees Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Uncollected Investment Advisory and Administrative Fees, Amount Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Uncollected Investment Advisory and Administrative Fees, Amount Maximum risk of loss related to nonconsolidated variable interest entities Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount New Accounting Guidance and Newly Issued But Not Yet Adopted Accounting Guidance New Accounting Pronouncements, Policy [Policy Text Block] Lesses Lessee, Leases [Policy Text Block] Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by (used in) operating activities Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization of property and equipment Depreciation, Nonproduction Stock-based compensation expense Share-based Compensation Net gains recognized on investments Net Gains (Losses) Recognized on Investments Net Gains (Losses) Recognized on Investments Net investments in T. Rowe Price investment products used to economically hedge supplemental savings plan liability Proceeds from (Payments for) Trading Securities, Short-term Net change in securities held by consolidated T. Rowe Price investment products Increase (Decrease) In Trading Securities, Consolidated Sponsored Investment Portfolios Increase (Decrease) in Trading Securities, Consolidated Sponsored Investment Portfolios Other changes in assets and liabilities Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Purchases of T. Rowe Price investment products Payments to Acquire Investments Dispositions T. Rowe Price investment products Proceeds from Sale, Maturity and Collection of Investments Net cash of T. Rowe Price investment products on consolidation (deconsolidation) Net Cash Flow For Consolidation Deconsolidation Of Sponsored Investment Portfolios The net cash inflow (outflow) associated with the consolidation (deconsolidation) of sponsored investment portfolios. Additions to property and equipment Payments to Acquire Property, Plant, and Equipment Other investing activity Payments for (Proceeds from) Other Investing Activities Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Repurchases of common stock Payments for Repurchase of Common Stock Common share issuances under stock-based compensation plans Proceeds from stock options exercised, net of payments for repurchase of common stock for employee tax withholding obligations and strike price The cash inflow associated with the amount received from holders exercising their stock options net of 1) shares swapped by the employee to pay the cost of related employee stock option awards and 2) cash outflows paid by the company to cover an employee's income tax withholding obligation as part of a net-share settlement of a share-based award. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately. A positive value represents cash inflows in excess of cash outflows listed. A negative value represents cash outflows in excess of the cash inflow described. Dividends paid to common stockholders of T. Rowe Price Group Payments of Dividends Net subscriptions received from redeemable non-controlling interest holders Proceeds from (Payments to) Noncontrolling Interests Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rate changes on cash and cash equivalents of consolidated T. Rowe Price investment products Effect of Exchange Rate on Cash and Cash Equivalents Net change in cash and cash equivalents during period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Condensed Cash Flow Statement [Table] Condensed Cash Flow Statement [Table] Voting interest entities [Member] Voting Interest Entities [Member] Voting Interest Entities [Member] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Reportable entities [Member] Reportable Legal Entities [Member] Consolidation eliminations [Member] Consolidation, Eliminations [Member] Condensed Cash Flow Statements, Captions [Line Items] Condensed Cash Flow Statements, Captions [Line Items] Net cash provided by operating activities Net cash used in investing activities Net cash used in financing activities Effect of exchange rate changes on cash and cash equivalents of consolidated T. Rowe Price investment products 2019 (excluding the first quarter ended March 31, 2019) Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year 2020 Lessee, Operating Lease, Liability, Payments, Due Year Two 2021 Lessee, Operating Lease, Liability, Payments, Due Year Three 2022 Lessee, Operating Lease, Liability, Payments, Due Year Four 2023 Lessee, Operating Lease, Liability, Payments, Due Year Five Thereafter Lessee, Operating Lease, Liability, Payments, Due after Year Five Total future undiscounted cash flows Lessee, Operating Lease, Liability, Payments, Due Less: imputed interest to be recognized in lease expense Lessee, Operating Lease, Liability, Undiscounted Excess Amount Operating lease liabilities, as reported Operating Lease, Liability Concentration Risk [Table] Concentration Risk [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Outside U.S. [Member] Non-US [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Assets under management [Member] Assets Under Management [Member] Assets Under Management [Member] Investment advisory clients [Member] Investment Advisory Clients [Member] Investment Advisory Clients [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Geographic concentration [Member] Geographic Concentration Risk [Member] Concentration Risk [Line Items] Concentration Risk [Line Items] Concentration risk, percentage Concentration Risk, Percentage Accounts receivable Accounts Receivable, Net Net unrealized holding gains [Member] Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] Consolidated T. Rowe Price investment products - variable interest entities [Member] AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Balances, As Adjusted Other comprehensive income (loss) before reclassifications and income taxes OCI, before Reclassifications, before Tax, Attributable to Parent Reclassification adjustments recognized in non-operating income Reclassification from AOCI, Current Period, before Tax, Attributable to Parent Other comprehensive income (loss), before taxes Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Net deferred tax benefits (income taxes) Other comprehensive income (loss) Accounting standards update 2018-02, available for sale securities [Member] Accounting Standards Update 2018-02, Available for Sale Securities [Member] Accounting Standards Update 2018-02, Available for Sale Securities [Member] Cash dividends declared (in USD per share) Common Stock, Dividends, Per Share, Declared STOCKHOLDERS’ EQUITY Stockholders' Equity Note Disclosure [Text Block] FAIR VALUE MEASUREMENTS Fair Value Disclosures [Text Block] Components of revenues from advisory services Components of Investment Advisory Fees [Table Text Block] Tabular disclosure of the components of revenue recognized in the period for schedule-based fees earned for management of mutual funds based on average daily net assets and other investment management and advisory fees earned on other client portfolios based on asset valuations. Components of assets under management Components of Assets Under Management [Table Text Block] Tabular disclosure of the components of average assets under management and period end assets under management. Assets under management represents the market value of assets an investment adviser manages on behalf of investors and is the basis for determining investment advisory fee revenue. Condensed Balance Sheet Statement [Table] Condensed Balance Sheet Statement [Table] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Money Market Funds [Member] Money Market Funds [Member] Condensed Balance Sheet Statements, Captions [Line Items] Condensed Balance Sheet Statements, Captions [Line Items] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Investments Other assets Other Assets Total assets Assets Liabilities Liabilities Net assets Net Assets Attributable to T. Rowe Price Group Investment, Sponsored Investment Portfolios, Attributable to Parent Represents the reporting entity's interest in consolidated sponsored investment portfolios. This amount is eliminated in consolidation. Attributable to redeemable non-controlling interests Net assets of consolidated sponsored investment portfolios Consolidated Sponsored Investment Portfolios Condensed Balance Sheet [Table Text Block] Tabular disclosure of condensed balance sheet for consolidated sponsored investment portfolios. Operating results of consolidated sponsored investment portfolios Consolidated Sponsored Investment Portfolios Condensed Income Statement [Table Text Block] Tabular disclosure of condensed income statement for consolidated sponsored investment portfolios. Cash flows of consolidated sponsored investment portfolios Consolidated Sponsored Investment Portfolios Condensed Cash Flow Statement [Table Text Block] Tabular disclosure of condensed cash flow statement of consolidated sponsored investment portfolios. Fair values of investments held by consolidated sponsored investment portfolios Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis for Consolidated Sponsored Investment Portfolios [Table Text Block] Tabular disclosure of assets and liabilities of consolidated sponsored investment portfolios that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). Earnings per share reconciliation Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Net unrealized holding gains or losses [Member] Reclassification adjustment out of accumulated other comprehensive income Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Non-operating income Provision for income taxes Income Tax Expense (Benefit) Reclassification adjustment of stranded taxes on available-for-sale investments Income Statement [Abstract] Administrative, distribution, and servicing fees [Member] Administrative, Distribution, And Servicing [Member] Administrative, Distribution, And Servicing [Member] Revenues Revenues, Net of Interest Expense [Abstract] Operating expenses Operating Expenses [Abstract] Compensation and related costs Labor and Related Expense Distribution and servicing Distribution Expenses Distribution Expenses Advertising and promotion Marketing and Advertising Expense Product-related costs Product-Related And Client Servicing Expenses Product-Related And Client Servicing Expenses Technology, occupancy, and facility costs Technology, Depreciation, Occupancy, And Facility Expenses Technology, Depreciation, Occupancy, And Facility Expenses General, administrative, and other Other General and Administrative Expense Total operating expenses Operating Expenses Net operating income Operating Income (Loss) Non-operating income Nonoperating Income (Expense) [Abstract] Net gains on investments Investment Income, Nonoperating, Other Than Consolidated Sponsored Investment Portfolios Investment Income, Nonoperating, Other Than Consolidated Sponsored Investment Portfolios Net gains on consolidated investment products Investment Income, Nonoperating, Consolidated Sponsored Investment Portfolios Investment Income, Nonoperating, Consolidated Sponsored Investment Portfolios Other income Other Nonoperating Income (Expense) Total non-operating income Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Provision for income taxes Net income Less: net income attributable to redeemable non-controlling interests Net income attributable to T. Rowe Price Group Earnings per share on common stock of T. Rowe Price Group Basic (in dollars per share) Earnings Per Share, Basic Diluted (in dollars per share) Earnings Per Share, Diluted Unconsolidated investments Investment [Table Text Block] Net impact of deconsolidation and consolidation on condensed consolidated balance sheets and income statements Schedule of Deconsolidation Impacts on Financial Statements [Table Text Block] Schedule of Deconsolidation Impacts on Financial Statements [Table Text Block] Maximum risk of loss related to investments in variable interest entities Schedule of Variable Interest Entities [Table Text Block] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Outstanding at December 31, 2018 (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Exercised (in shares) Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Expired (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period Outstanding at March 31, 2019 (in shares) Exercisable at March 31, 2019 (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Weighted-average exercise price of options outstanding at December 31, 2018 (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Weighted-average exercise price of options exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Weighted-average exercise price of options forfeited (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Weighted-average exercise price of options expired (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Weighted-average exercise price of options outstanding at March 31, 2019 (in dollars per share) Weighted-average exercise price of options exercisable at March 31, 2019 (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Accounts receivable and accrued revenue Assets of consolidated T. Rowe Price investment products ($1,620.6 million at March 31, 2019 and $1,392.6 million at December 31, 2018, related to variable interest entities) Variable Interest Entity, Consolidated, Carrying Amount, Assets Operating lease assets Operating Lease, Right-of-Use Asset Property and equipment, net Property, Plant and Equipment, Net Goodwill Goodwill LIABILITIES Liabilities [Abstract] Accounts payable and accrued expenses Accounts Payable and Other Accrued Liabilities Liabilities of consolidated T. Rowe Price investment products ($41.1 million at March 31, 2019 and $22.7 million at December 31, 2018, related to variable interest entities) Variable Interest Entity, Consolidated, Carrying Amount, Liabilities Operating lease liabilities Accrued compensation and related costs Employee-related Liabilities Supplemental savings plan liability Deferred Compensation Arrangement with Individual, Recorded Liability Income taxes payable Accrued Income Taxes Total liabilities Commitments and contingent liabilities Commitments and Contingencies Redeemable non-controlling interests STOCKHOLDERS’ EQUITY Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, undesignated, $.20 par value – authorized and unissued 20,000,000 shares Preferred Stock, Value, Issued Common stock, $.20 par value—authorized 750,000,000; issued 236,432,000 shares at March 31, 2019 and 238,069,000 at December 31, 2018 Common Stock, Value, Issued Additional capital in excess of par value Additional Paid in Capital, Common Stock Retained earnings Retained Earnings, Unappropriated Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total permanent stockholders’ equity Total liabilities, redeemable non-controlling interests, and permanent stockholders’ equity Liabilities and Equity Weighted-average remaining lease term on operating leases Operating Lease, Weighted Average Remaining Lease Term Weighted-average discount rate on operating leases Operating Lease, Weighted Average Discount Rate, Percent Operating lease expense Operating Lease, Expense Variable charges related to operating leases not included in measurement of lease liability Variable Lease, Cost Cash paid included in measurement of operating lease liabilities Operating Lease, Payments INVESTMENTS Investment [Text Block] Schedule of future minimum lease payments Lessee, Operating Lease, Liability, Maturity [Table Text Block] Condensed Income Statement [Table] Condensed Income Statement [Table] Investment advisory and administrative fees Investment Advisory, Management and Administrative Service [Member] Condensed Income Statements, Captions [Line Items] Condensed Income Statements, Captions [Line Items] Operating expenses reflected in net operating income Net investment income (loss) reflected in non-operating income Investment Income, Nonoperating Net income (loss) attributable to T. Rowe Price Group Income (Loss) from Continuing Operations before Income Taxes, Attributable to Parent Income (Loss) from Continuing Operations before Income Taxes, Attributable to Parent Operating expenses eliminated against investment advisory and administrative fees New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] ASU 2016-02 - Leases [Member] Accounting Standards Update 2016-02 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Operating lease assets, including deferred rent liabilities reclassified Operating Lease, Right-Of-Use Asset, Excluding Deferred Rent Liabilities To Be Reclassified Operating Lease, Right-Of-Use Asset, Excluding Deferred Rent Liabilities to be Reclassified Deferred rent liabilities Deferred Rent Credit Document and Entity Information [Abstract] Document and Entity Information [Abstract] Document Type Document Type Document Period End Date Document Period End Date Current Fiscal Year End Date Current Fiscal Year End Date Document Fiscal Period Focus Document Fiscal Period Focus Document Fiscal Year Focus Document Fiscal Year Focus Entity Registrant Name Entity Registrant Name Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding (shares) Entity Common Stock, Shares Outstanding Entity Central Index Key Entity Central Index Key Amendment Flag Amendment Flag Entity Emerging Growth Company Entity Emerging Growth Company Entity Small Business Entity Small Business Commitments and Contingencies Disclosure [Abstract] COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Assets of consolidated T. Rowe Price investment products Liabilities of consolidated T. Rowe Price investment products Stockholders' equity Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Common stock, shares issued (in shares) Common Stock, Shares, Issued