v2.4.1.9

Carrying Value and Fair Value of Blackstone Issued Notes (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified | 3 Months Ended |
--- | --- | ---
Mar. 31, 2015 | Dec. 31, 2012
Debt Instrument [Line Items] |  |
Senior Notes |  | $ 600 us-gaap_SeniorNotes
Notes acquired not retired |  | 15 bx_NotesAcquiredNotRetired
6.625% Notes |  |
Debt Instrument [Line Items] |  |
Debt instrument, interest rate | 6.625%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = bx_SixPointSixTwoFivePercentNotesMember |
Debt instrument, maturity date | Aug. 15, 2019 |
Senior Notes | 600 us-gaap_SeniorNotes / us-gaap_DebtInstrumentAxis = bx_SixPointSixTwoFivePercentNotesMember |
5.875% Notes |  |
Debt Instrument [Line Items] |  |
Debt instrument, interest rate | 5.875%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = bx_FivePointEightSevenFivePercentNotesMember |
Debt instrument, maturity date | Mar. 15, 2021 |
Senior Notes | 400 us-gaap_SeniorNotes / us-gaap_DebtInstrumentAxis = bx_FivePointEightSevenFivePercentNotesMember |
4.750% Notes |  |
Debt Instrument [Line Items] |  |
Debt instrument, interest rate | 4.75%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = bx_FourPointSevenFiveZeroPercentNotesMember |
Debt instrument, maturity date | Feb. 15, 2023 |
Senior Notes | 400 us-gaap_SeniorNotes / us-gaap_DebtInstrumentAxis = bx_FourPointSevenFiveZeroPercentNotesMember |
6.250% Notes |  |
Debt Instrument [Line Items] |  |
Debt instrument, interest rate | 6.25%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = bx_SixPointTwoFiveZeroPercentNotesMember |
Debt instrument, maturity date | Aug. 15, 2042 |
Senior Notes | 250 us-gaap_SeniorNotes / us-gaap_DebtInstrumentAxis = bx_SixPointTwoFiveZeroPercentNotesMember |
5.000% Notes |  |
Debt Instrument [Line Items] |  |
Debt instrument, interest rate | 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = bx_FivePointZeroZeroZeroPercentNotesMember |
Debt instrument, maturity date | Jun. 15, 2044 |
Senior Notes | $ 500 us-gaap_SeniorNotes / us-gaap_DebtInstrumentAxis = bx_FivePointZeroZeroZeroPercentNotesMember |

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- Definition Notes Acquired but not Retired. + References No definition available. + Details
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Namespace Prefix: | bx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Details
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Period Type: | duration

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- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16(a)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 + Details
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Period Type: | instant

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