CONSOLIDATED T. ROWE PRICE INVESTMENT PRODUCTS. (Statement of Cash Flows) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	$ 578.7	$ 521.0
Net cash used in investing activities	(33.8)	(519.8)
Net cash used in financing activities	(306.0)	(242.1)
Effect of exchange rate changes on cash and cash equivalents of consolidated T. Rowe Price investment products	(0.7)	1.3
Net change in cash and cash equivalents during period	238.2	(239.6)
Cash and cash equivalents at beginning of period	1,495.3	2,005.8
Cash and cash equivalents at end of period	1,733.5	1,766.2
Consolidation eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash used in financing activities	(37.8)	(25.1)
Consolidated T. Rowe Price investment products [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash and cash equivalents at beginning of period	70.1	103.1
Cash and cash equivalents at end of period	76.1	84.8
Consolidated T. Rowe Price investment products [Member] \| Reportable entities [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	(93.7)	(201.0)
Net cash used in investing activities	(3.4)	(21.5)
Net cash used in financing activities	103.8	202.9
Effect of exchange rate changes on cash and cash equivalents of consolidated T. Rowe Price investment products	(0.7)	1.3
Net change in cash and cash equivalents during period	6.0	(18.3)
Cash and cash equivalents at beginning of period	103.1	70.1
Cash and cash equivalents at end of period	84.8	76.1
Voting interest entities [Member] \| Reportable entities [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	(28.7)	(52.8)
Net cash used in investing activities	(5.1)	0.0
Net cash used in financing activities	31.6	63.4
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	(2.2)	10.6
Cash and cash equivalents at beginning of period	7.1	18.5
Cash and cash equivalents at end of period	17.7	16.3
Variable interest entities [Member] \| Reportable entities [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	(65.0)	(148.2)
Net cash used in investing activities	1.7	(21.5)
Net cash used in financing activities	72.2	139.5
Effect of exchange rate changes on cash and cash equivalents of consolidated T. Rowe Price investment products	(0.7)	1.3
Net change in cash and cash equivalents during period	8.2	(28.9)
Cash and cash equivalents at beginning of period	96.0	51.6
Cash and cash equivalents at end of period	$ 67.1	$ 59.8

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Cash and Cash Equivalents, at Carrying Value, Including Consolidated Sponsored Investment Portfolios

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