v3.3.0.814

Borrowings - Additional Information (Detail) - USD ($) $ in Billions	Sep. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Fair value of the CLO assets	$ 4.1	$ 8.0

X

- Definition

Fair Value of the CLO Assets

+ References

No definition available.

+ Details

Name:	bx_FairValueOfCLOAssets
Namespace Prefix:	bx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- 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

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration