INVESTMENTS. (Variable Interest Entities) (Details) - Variable interest entity, not primary beneficiary - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Investment carrying values	$ 129.4	$ 156.0
Unfunded capital commitments	15.6	18.1
Uncollected investment advisory and administrative fees	7.1	10.5
Maximum risk of loss related to nonconsolidated variable interest entities	$ 152.1	$ 184.6

Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Investment Carrying Values, Amount

No definition available.

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Namespace Prefix:	trow_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Uncollected Investment Advisory and Administrative Fees, Amount

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Unfunded Capital Commitments, Amount

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118582676&loc=d3e5747-111685

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph b
-URI http://asc.fasb.org/extlink&oid=118582676&loc=d3e5728-111685

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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Period Type:	duration

- Details

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