v2.4.0.8

Unvested Units, After Expected Forfeitures (Detail) | 9 Months Ended
--- | ---
Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Blackstone Holdings Partnership Units (Units) | 46,743,135
Deferred Restricted Blackstone Common Units and Options (Units) | 16,398,203
Total Equity-Based Awards (Units) | 63,141,338
Phantom Units (Units) | 142,313
Blackstone Holdings Partnership Units (Weighted-Average Service Period in Years) | 2 years 1 month 6 days
Deferred Restricted Blackstone Common Units and Options (Weighted-Average Service Period in Years) | 2 years 6 months
Total Equity-Based Awards (Weighted-Average Service Period in Years) | 2 years 2 months 12 days
Phantom Units (Weighted-Average Service Period in Years) | 1 year 8 months 12 days

X
- Definition Deferred Restricted Common Units And Options, Weighted Average Service Period + References No definition available. + Details
Name: | bx_DeferredRestrictedCommonUnitsAndOptionsWeightedAverageServicePeriod
Namespace Prefix: | bx_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Partnership Units Weighted Average Service Period + References No definition available. + Details
Name: | bx_PartnershipUnitsWeightedAverageServicePeriod
Namespace Prefix: | bx_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Phantom Units, Weighted Average Service Period + References No definition available. + Details
Name: | bx_PhantomUnitsWeightedAverageServicePeriod
Namespace Prefix: | bx_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total Equity Based Awards, Weighted Average Service Period + References No definition available. + Details
Name: | bx_TotalEquityBasedAwardsWeightedAverageServicePeriod
Namespace Prefix: | bx_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Units Expected To Vest Deferred Restricted Common Units And Options + References No definition available. + Details
Name: | bx_UnitsExpectedToVestDeferredRestrictedCommonUnitsAndOptions
Namespace Prefix: | bx_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Units Expected To Vest For Partnership Units + References No definition available. + Details
Name: | bx_UnitsExpectedToVestForPartnershipUnits
Namespace Prefix: | bx_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Units Expected To Vest For Phantom Units + References No definition available. + Details
Name: | bx_UnitsExpectedToVestForPhantomUnits
Namespace Prefix: | bx_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Units Expected To Vest For Total Equity Based Awards + References No definition available. + Details
Name: | bx_UnitsExpectedToVestForTotalEquityBasedAwards
Namespace Prefix: | bx_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration