CONSOLIDATED T. ROWE PRICE INVESTMENT PRODUCTS. (Statement of Cash Flows) (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	$ 948.8	$ 929.3
Net cash used in investing activities	(29.1)	(944.0)
Net cash used in financing activities	(501.5)	(388.2)
Effect of exchange rate changes on cash and cash equivalents of consolidated T. Rowe Price investment products	(0.4)	(6.6)
Net change in cash and cash equivalents during period	417.8	(409.5)
Cash and cash equivalents at beginning of period	1,495.3	2,005.8
Cash and cash equivalents at end of period	1,913.1	1,596.3
Consolidation eliminations [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash used in financing activities	146.9	115.6
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	110.7	111.9
Consolidated T. Rowe Price investment products [Member] \| Reportable entities [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	(291.1)	(396.5)
Net cash used in investing activities	(5.1)	(21.7)
Net cash used in financing activities	337.2	433.6
Effect of exchange rate changes on cash and cash equivalents of consolidated T. Rowe Price investment products	(0.4)	(6.6)
Net change in cash and cash equivalents during period	40.6	8.8
Cash and cash equivalents at beginning of period	70.1	103.1
Cash and cash equivalents at end of period	110.7	111.9
Voting interest entities [Member] \| Reportable entities [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	(32.7)	(38.1)
Net cash used in investing activities	(5.1)	0.0
Net cash used in financing activities	34.5	57.1
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	(3.3)	19.0
Cash and cash equivalents at beginning of period	18.5	7.1
Cash and cash equivalents at end of period	15.2	26.1
Variable interest entities [Member] \| Reportable entities [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	(258.4)	(358.4)
Net cash used in investing activities	0.0	(21.7)
Net cash used in financing activities	302.7	376.5
Effect of exchange rate changes on cash and cash equivalents of consolidated T. Rowe Price investment products	(0.4)	(6.6)
Net change in cash and cash equivalents during period	43.9	(10.2)
Cash and cash equivalents at beginning of period	51.6	96.0
Cash and cash equivalents at end of period	$ 95.5	$ 85.8

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

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Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

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