v2.4.0.6

COMMITMENTS AND CONTINGENCIES - Additional Information (Detail) (USD $) | 6 Months Ended
--- | ---
Jun. 30, 2012
Schedule Of Commitments And Contingencies [Line Items] |
General partner capital funding | $ 1,300,000,000
Total investments at risk in respect of guarantees extended | 4,900,000
Loans held By employees for investment guaranteed | 41,600,000
Contingent obligations currently anticipated to expire start | 2012
Contingent obligations currently anticipated to expire end | 2018
Provision for cash clawback | 412,100,000
Blackstone Funds |
Schedule Of Commitments And Contingencies [Line Items] |
Funds signed investment commitments | 53,200,000
Portfolio Company Acquisition | Blackstone Funds |
Schedule Of Commitments And Contingencies [Line Items] |
Signed investment commitments for portfolio company acquisitions in process of closing | $ 30,300,000

X
- Definition Contingent obligations currently anticipated to expire end + References No definition available. + Details
Name: | bx_ContingentObligationsCurrentlyAnticipatedToExpireEnd
Namespace Prefix: | bx_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Contingent Obligations Currently Anticipated to Expire Start + References No definition available. + Details
Name: | bx_ContingentObligationsCurrentlyAnticipatedToExpireStart
Namespace Prefix: | bx_
Data Type: | xbrli:gYearItemType
Balance Type: | na
Period Type: | duration

X
- Definition Funds Signed Investment Commitments + References No definition available. + Details
Name: | bx_FundsSignedInvestmentCommitments
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition General Partner Capital Funding Commitments + References No definition available. + Details
Name: | bx_GeneralPartnerCapitalFundingCommitments
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Loans Held By Employees For Investment Guaranteed + References No definition available. + Details
Name: | bx_LoansHeldByEmployeesForInvestmentGuaranteed
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Provision for cash clawback + References No definition available. + Details
Name: | bx_ProvisionForCashClawback
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | bx_ScheduleOfCommitmentsAndContingenciesLineItems
Namespace Prefix: | bx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Signed Investment Commitments For Portfolio Company Acquisitions In Process Of Closing + References No definition available. + Details
Name: | bx_SignedInvestmentCommitmentsForPortfolioCompanyAcquisitionsInProcessOfClosing
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents disclosure of all significant concentrations of credit risk or market risk arising from the subject financial instrument (as defined), whether from an individual counterparty or groups of counterparties. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Available-for-Sale Securities -URI http://asc.fasb.org/extlink&oid=6505594 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 12 -Subparagraph a -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph a, f, g -Article 7 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 13 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=7534914&loc=d3e22054-111558 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 107 -Paragraph 15C -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 107 -Paragraph 15A -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 107 -Paragraph 15D -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_FairValueConcentrationOfRiskInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant