Variable Interest Entities - Consolidated Variable Interest Entities (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Jan. 01, 2016
Assets
Cash and cash equivalents	$ 123,035	$ 121,711	$ 97,951	$ 93,439
Loans receivable	50,385	49,672
Financial instruments owned, at fair value	308,871	295,952
Other assets	26,844	25,481
Liabilities
Other secured financings	22,376	21,523
Payables to brokers, dealers and clearing organizations	8,589	4,386
Financial instruments sold, but not yet purchased, at fair value	115,927	117,143
Unsecured short-term borrowings	35,872	39,265
Unsecured long-term borrowings	199,370	189,086
Other liabilities and accrued expenses	11,189	14,362
Real Estate, Credit-Related and Other Investing [Member]
Assets
Cash and cash equivalents	323	300
Loans receivable	528	603
Financial instruments owned, at fair value	1,917	1,708
Other assets	580	680
Total	3,348	3,291
Liabilities
Other secured financings	304	284
Payables to brokers, dealers and clearing organizations	9	1
Financial instruments sold, but not yet purchased, at fair value	15	7
Other liabilities and accrued expenses	959	803
Total	1,287	1,095
CDOs, Mortgage-Backed and Other Asset-Backed [Member]
Assets
Cash and cash equivalents	674
Financial instruments owned, at fair value	251	253
Other assets	9	2
Total	934	255
Liabilities
Other secured financings	825	139
Total	825	139
Principal-Protected Notes [Member]
Assets
Financial instruments owned, at fair value	88	86
Total	88	86
Liabilities
Other secured financings	432	431
Unsecured short-term borrowings	212	197
Unsecured long-term borrowings	323	334
Total	967	962
Consolidated Variable Interest Entity, Total Carrying Amount [Member]
Assets
Cash and cash equivalents	997	300
Loans receivable	528	603
Financial instruments owned, at fair value	2,256	2,047
Other assets	589	682
Total	4,370	3,632
Liabilities
Other secured financings	1,561	854
Payables to brokers, dealers and clearing organizations	9	1
Financial instruments sold, but not yet purchased, at fair value	15	7
Unsecured short-term borrowings	212	197
Unsecured long-term borrowings	323	334
Other liabilities and accrued expenses	959	803
Total	$ 3,079	$ 2,196