Variable Interest Entities and Securitization Activities (Assets and Liabilities by Balance Sheet Caption) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Assets
Cash and due from banks	$ 22,017	$ 19,827	$ 19,827	$ 21,381
Trading assets, at fair value	262,154	239,505
Customer and other receivables	46,460	45,407
Goodwill	6,577	6,584		$ 6,588
Intangible assets	2,721	2,984
Other assets	52,125	51,087
Assets	814,949	787,465
Liabilities
Other secured financings, fair value	5,041	2,854
Other liabilities and accrued expenses	15,896	18,711
Liabilities	737,772	711,281
Noncontrolling interests	1,127	1,002
Additional maximum exposure to losses	78	72
Consolidated VIEs
Assets
Cash and due from banks	74	14
Trading assets, at fair value	1,295	1,842
Customer and other receivables	13	3
Goodwill	18	0
Intangible assets	177	0
Other assets	833	741
Assets	2,410	2,600
Liabilities
Other secured financings, fair value	289	431
Other liabilities and accrued expenses	29	5
Liabilities	318	436
Noncontrolling interests	$ 228	$ 37