SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Investments) (Detail)	12 Months Ended
Dec. 31, 2014
Available-for-sale Securities [Abstract]
Duration of fund holding unrealized loss between quarter ends generally presumed to represent other than temporary impairment	6 months

The period of time between quarter ends after which available-for-sale equity securities in a continuous unrealized loss position will generally be considered other than temporarily impaired under the company's impairment policy.

No definition available.

Name:	trow_AvailableForSaleEquitySecuritiesInUnrealizedLossPositionQualitativeDisclosureOtherThanTemporaryImpairmentPolicyLossTerm
Namespace Prefix:	trow_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration