v3.3.0.814

Performance Fees Allocated to Funds (Detail) $ in Thousands | 9 Months Ended
--- | ---
Sep. 30, 2015 USD ($)
Schedule of Performance Fees and Allocations to the General Partner [Line Items] |
Performance Fees, December 31, 2014 | $ 6,337,045
Performance Fees Allocated as a Result of Changes in Fund Fair Values | 1,516,594
Foreign Exchange Loss | (20,321)
Fund Distributions | (2,613,204)
Performance Fees, September 30, 2015 | 5,220,114
Private Equity Segment |
Schedule of Performance Fees and Allocations to the General Partner [Line Items] |
Performance Fees, December 31, 2014 | 2,215,584
Performance Fees Allocated as a Result of Changes in Fund Fair Values | 595,918
Fund Distributions | (1,164,109)
Performance Fees, September 30, 2015 | 1,647,393
Real Estate Segment |
Schedule of Performance Fees and Allocations to the General Partner [Line Items] |
Performance Fees, December 31, 2014 | 3,721,751
Performance Fees Allocated as a Result of Changes in Fund Fair Values | 882,083
Foreign Exchange Loss | (20,321)
Fund Distributions | (1,334,908)
Performance Fees, September 30, 2015 | 3,248,605
Hedge Fund Solutions Segment |
Schedule of Performance Fees and Allocations to the General Partner [Line Items] |
Performance Fees, December 31, 2014 | 15,031
Performance Fees Allocated as a Result of Changes in Fund Fair Values | 29,019
Fund Distributions | (12,526)
Performance Fees, September 30, 2015 | 31,524
Credit Segment |
Schedule of Performance Fees and Allocations to the General Partner [Line Items] |
Performance Fees, December 31, 2014 | 384,679
Performance Fees Allocated as a Result of Changes in Fund Fair Values | 9,574
Fund Distributions | (101,661)
Performance Fees, September 30, 2015 | $ 292,592

X
- Definition Foreign Currency Exchange Gain Loss + References No definition available. + Details
Name: | bx_ForeignCurrencyExchangeGainLoss
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fund Distributions + References No definition available. + Details
Name: | bx_FundDistributions
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Performance Fees Allocated As Result Of Changes In Fund Fair Values + References No definition available. + Details
Name: | bx_PerformanceFeesAllocatedAsResultOfChangesInFundFairValues
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Performance Fees Receivable + References No definition available. + Details
Name: | bx_PerformanceFeesReceivable
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Schedule of Performance Fees and Allocations to the General Partner [Line Items] + References No definition available. + Details
Name: | bx_ScheduleOfPerformanceFeesAndAllocationsToGeneralPartnerLineItems
Namespace Prefix: | bx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=bx_PrivateEquitySegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=bx_RealEstateSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=bx_HedgeFundSolutionsSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=bx_CreditSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |