Investments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Schedule of Investments [Line Items]
Equity Method Investments	$ 2,582,504	$ 2,218,103
Blackstone's Treasury Cash Management Strategies	1,411,680	685,859
Performance Fees	2,780,217	1,889,152
Other Investments	46,124	28,390
Investments	20,847,270	15,128,299
Consolidated Blackstone Funds
Schedule of Investments [Line Items]
Investments of Consolidated Blackstone Funds	$ 14,026,745	$ 10,306,795

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.12)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=16385135&loc=d3e33749-111570

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