v2.4.1.9

Reconciliation of Total Segments to Income Before Provision for Taxes and Total Assets (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified | 3 Months Ended
--- | ---
Mar. 31, 2015 | Mar. 31, 2014
Segment Reporting Information [Line Items] |  |
Fund Management Fees and Performance Fees Eliminated in Consolidation and Transactional Investment Loss | $ 15,067 bx_FundManagementFeesAndPerformanceFeesEliminatedInConsolidation | $ (17,878)bx_FundManagementFeesAndPerformanceFeesEliminatedInConsolidation
Fund Expenses Added in Consolidation | 15,748 bx_FundExpensesAddedInConsolidation | (746)bx_FundExpensesAddedInConsolidation
Non-Controlling Interests in Income of Consolidated Entities | 209,580 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | 89,753 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest
Transaction-Related Other Loss | (1,423)bx_TransactionRelatedOtherIncomeExpense | (974)bx_TransactionRelatedOtherIncomeExpense
Total Other Income | 238,972 us-gaap_OtherNonoperatingIncomeExpense | 70,155 us-gaap_OtherNonoperatingIncomeExpense
Economic Income | 1,631,783 bx_EconomicIncome | 825,246 bx_EconomicIncome
Amortization of Intangibles | (25,899)bx_SegmentReconciliationAmortizationOfIntangibleAssets | (29,003)bx_SegmentReconciliationAmortizationOfIntangibleAssets
IPO and Acquisition-Related Charges | (231,862)bx_IpoAndAcquisitionRelatedCharges | (177,024)bx_IpoAndAcquisitionRelatedCharges
Non-Controlling Interests in Income of Consolidated Entities | 209,580 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | 89,753 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest
Total Consolidation Adjustments and Reconciling Items | (48,181)bx_ConsolidationAdjustmentsAndReconcilingItemsForEconomicIncomeToIncomeBeforeProvisionForTaxes | (116,274)bx_ConsolidationAdjustmentsAndReconcilingItemsForEconomicIncomeToIncomeBeforeProvisionForTaxes
Income Before Provision for Taxes | $ 1,583,602 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest | $ 708,972 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest

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- Definition Consolidation Adjustments and Reconciling Items for Economic Income to Income Before Provision for Taxes. + References No definition available. + Details
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Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Definition Economic Income + References No definition available. + Details
Name: | bx_EconomicIncome
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- Definition Fund Expenses Added in Consolidation + References No definition available. + Details
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Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- Definition Fund Management Fees And Performance Fees Eliminated In Consolidation + References No definition available. + Details
Name: | bx_FundManagementFeesAndPerformanceFeesEliminatedInConsolidation
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- Definition IPO And Acquisition Related Charges + References No definition available. + Details
Name: | bx_IpoAndAcquisitionRelatedCharges
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Definition Segment Reconciliation Amortization Of Intangible Assets + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
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- Definition Transaction Related Other Income (Expense) + References No definition available. + Details
Name: | bx_TransactionRelatedOtherIncomeExpense
Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- Definition This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 940 -SubTopic 20 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=35710027&loc=d3e41242-110953 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 10 -Article 5 + Details
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- Definition Amount of Net Income (Loss) attributable to noncontrolling interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 55 -Paragraph 4J -URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591551-111686 + Details
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Balance Type: | debit
Period Type: | duration

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- Definition The net amount of other income and expense amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income (expense) recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) net gains or losses on securities, (d) unusual costs, (e) gains or losses on foreign exchange transactions, and (f) miscellaneous other income and expense items. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.9) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
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Period Type: | duration

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- Details
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Period Type: | duration