v2.4.0.6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional information (Detail) (USD $) | 3 Months Ended | 6 Months Ended | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Jun. 30, 2012 | Jun. 30, 2011 | Jun. 30, 2012 | Jun. 30, 2011 | Jun. 30, 2011 Redeemable Non - Controlling Interest | Jun. 30, 2011 Redeemable Non - Controlling Interest | Dec. 31, 2011 Redeemable Non - Controlling Interest
Variable Interest Entity [Line Items] |  |  |  |  |  |  |
Adjustment to Redeemable Non-Controlling Interests |  |  |  |  |  |  | $ 506,200,000
Net Gains (Losses) from Fund Investment Activities attributable to Redeemable Non-Controlling Interests in Consolidated Entities | $ 248,230,000 | $ (74,654,000) | $ 536,372,000 | $ (119,845,000) | $ 300,000 | $ 1,100,000 |

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- Definition Net Gains (Losses) from Fund Investment Activities relating to the Partnership's consolidated noncontrolling interests in the Funds. + 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 Prior Period Adjustments + 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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- Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration