Variable Interest Entities - Nonconsolidated Variable Interest Entities (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Assets in VIE	$ 76,010	$ 90,145
Carrying Value of the Firm's Variable Interests in Nonconsolidated VIEs - Assets	6,562	7,171
Maximum Exposure to Loss in Nonconsolidated VIEs	14,905	15,751
Carrying Value of the Firm's Variable Interests in Nonconsolidated VIEs - Liabilities	252	177
Retained Interests, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	1,880	1,159
Purchased Interests, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	634	1,528
Commitments and Guarantees, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	2,616	2,020
Derivatives, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	6,053	6,936
Loans and Investments, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	3,722	4,108
Mortgage-Backed Securities [Member]
Variable Interest Entity [Line Items]
Assets in VIE	40,021	62,672
Carrying Value of the Firm's Variable Interests in Nonconsolidated VIEs - Assets	2,340	2,439
Maximum Exposure to Loss in Nonconsolidated VIEs	2,518	2,701
Mortgage-Backed Securities [Member] | Retained Interests, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	1,817	1,115
Mortgage-Backed Securities [Member] | Purchased Interests, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	523	1,324
Mortgage-Backed Securities [Member] | Commitments and Guarantees, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	10	40
Mortgage-Backed Securities [Member] | Derivatives, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	168	222
Corporate CDOs and CLOs [Member]
Variable Interest Entity [Line Items]
Assets in VIE	5,071	6,493
Carrying Value of the Firm's Variable Interests in Nonconsolidated VIEs - Assets	335	624
Maximum Exposure to Loss in Nonconsolidated VIEs	3,008	3,654
Carrying Value of the Firm's Variable Interests in Nonconsolidated VIEs - Liabilities	26	29
Corporate CDOs and CLOs [Member] | Retained Interests, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	2	3
Corporate CDOs and CLOs [Member] | Purchased Interests, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	68	106
Corporate CDOs and CLOs [Member] | Commitments and Guarantees, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	1,077	647
Corporate CDOs and CLOs [Member] | Derivatives, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	1,823	2,633
Corporate CDOs and CLOs [Member] | Loans and Investments, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	38	265
Real Estate, Credit-Related and Other Investing [Member]
Variable Interest Entity [Line Items]
Assets in VIE	8,922	9,793
Carrying Value of the Firm's Variable Interests in Nonconsolidated VIEs - Assets	2,689	3,557
Maximum Exposure to Loss in Nonconsolidated VIEs	3,165	4,127
Carrying Value of the Firm's Variable Interests in Nonconsolidated VIEs - Liabilities	3	3
Real Estate, Credit-Related and Other Investing [Member] | Commitments and Guarantees, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	476	570
Real Estate, Credit-Related and Other Investing [Member] | Loans and Investments, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	2,689	3,557
Other Asset-Backed [Member]
Variable Interest Entity [Line Items]
Assets in VIE	6,522	7,026
Carrying Value of the Firm's Variable Interests in Nonconsolidated VIEs - Assets	301	265
Maximum Exposure to Loss in Nonconsolidated VIEs	4,757	4,714
Carrying Value of the Firm's Variable Interests in Nonconsolidated VIEs - Liabilities	222	145
Other Asset-Backed [Member] | Retained Interests, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	61	41
Other Asset-Backed [Member] | Purchased Interests, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	43	98
Other Asset-Backed [Member] | Commitments and Guarantees, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	500	500
Other Asset-Backed [Member] | Derivatives, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	4,056	4,075
Other Asset-Backed [Member] | Loans and Investments, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	97
Investments in Funds and Other [Member]
Variable Interest Entity [Line Items]
Assets in VIE	15,474	4,161
Carrying Value of the Firm's Variable Interests in Nonconsolidated VIEs - Assets	897	286
Maximum Exposure to Loss in Nonconsolidated VIEs	1,457	555
Carrying Value of the Firm's Variable Interests in Nonconsolidated VIEs - Liabilities	1
Investments in Funds and Other [Member] | Commitments and Guarantees, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	553	263
Investments in Funds and Other [Member] | Derivatives, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	6	6
Investments in Funds and Other [Member] | Loans and Investments, Maximum Exposure to Loss [Member]
Variable Interest Entity [Line Items]
Maximum Exposure to Loss in Nonconsolidated VIEs	$ 898	$ 286