v2.4.1.9

Unvested Units, After Expected Forfeitures (Detail) | 3 Months Ended
--- | ---
Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Blackstone Holdings Partnership Units (Units) | 44,918,574 bx_UnitsExpectedToVestForPartnershipUnits
Deferred Restricted Blackstone Common Units | 14,948,369 bx_UnitsExpectedToVestDeferredRestrictedCommonUnits
Total Equity-Based Awards (Units) | 59,866,943 bx_UnitsExpectedToVestForTotalEquityBasedAwards
Phantom Units (Units) | 1,289 bx_UnitsExpectedToVestForPhantomUnits
Blackstone Holdings Partnership Units (Weighted-Average Service Period in Years) | 3 years 2 months 12 days
Deferred Restricted Blackstone Common Units | 2 years 2 months 12 days
Total Equity-Based Awards (Weighted-Average Service Period in Years) | 2 years 10 months 24 days
Phantom Units (Weighted-Average Service Period in Years) | 2 years 6 months

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

X
- Definition Units Expected To Vest Deferred Restricted Common Units + References No definition available. + Details
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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
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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
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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
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration