CONSOLIDATED T. ROWE PRICE INVESTMENT PRODUCTS. (Statement of Cash Flows) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 994.7	$ 787.7
Net cash used in investing activities	(30.8)	27.6
Net cash provided by financing activities	(307.5)	(992.3)
Effect of exchange rate changes on cash and cash equivalents of consolidated T. Rowe Price investment products	0.9	(1.2)
Net change in cash and cash equivalents during period	657.3	(178.2)
Cash and cash equivalents at beginning of period	2,256.5	1,858.3
Cash and cash equivalents at ending of period	2,913.8	1,680.1
Consolidated T. Rowe Price investment products
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents at beginning of period	104.8	76.5
Cash and cash equivalents at ending of period	83.7	117.7
Reportable entities \| Consolidated T. Rowe Price investment products
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(143.7)	(75.7)
Net cash used in investing activities	(27.3)	(0.8)
Net cash provided by financing activities	149.0	118.9
Effect of exchange rate changes on cash and cash equivalents of consolidated T. Rowe Price investment products	0.9	(1.2)
Net change in cash and cash equivalents during period	(21.1)	41.2
Cash and cash equivalents at beginning of period	104.8	76.5
Cash and cash equivalents at ending of period	83.7	117.7
Reportable entities \| Voting interest entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(31.7)	11.3
Net cash used in investing activities	(9.1)	(0.8)
Net cash provided by financing activities	36.7	2.7
Effect of exchange rate changes on cash and cash equivalents of consolidated T. Rowe Price investment products	0.0	0.0
Net change in cash and cash equivalents during period	(4.1)	13.2
Cash and cash equivalents at beginning of period	7.1	9.9
Cash and cash equivalents at ending of period	3.0	23.1
Reportable entities \| Variable interest entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(112.0)	(87.0)
Net cash used in investing activities	(18.2)	0.0
Net cash provided by financing activities	112.3	116.2
Effect of exchange rate changes on cash and cash equivalents of consolidated T. Rowe Price investment products	0.9	(1.2)
Net change in cash and cash equivalents during period	(17.0)	28.0
Cash and cash equivalents at beginning of period	97.7	66.6
Cash and cash equivalents at ending of period	80.7	94.6
Consolidation eliminations \| Consolidated T. Rowe Price investment products
Condensed Cash Flow Statements, Captions [Line Items]
Subscriptions payment, net of dividends received	$ 34.1	$ (42.8)

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