Variable Interest Entities and Securitization Activities (Assets and Liabilities by Balance Sheet Caption) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Cash and cash equivalents:
Cash and due from banks	$ 29,073	$ 24,816	$ 22,081
Restricted cash	35,291	34,231	$ 36,027
Trading assets at fair value	273,044	298,282
Customer and other receivables	66,835	56,187
Goodwill	6,706	6,597
Intangible assets	2,427	2,448
Other assets	16,282	16,628
Total assets	858,495	851,733
Liabilities
Other secured financings at fair value	3,423	3,863
Other liabilities and accrued expenses	14,265	17,157
Total liabilities	779,006	773,267
Noncontrolling interests	1,455	1,075
Consolidated VIEs
Cash and cash equivalents:
Cash and due from banks	103	69
Restricted cash	223	222
Trading assets at fair value	2,345	833
Customer and other receivables	21	19
Goodwill	18	18
Intangible assets	149	155
Other assets	454	485
Total assets	3,313	1,801
Liabilities
Other secured financings at fair value	1,305	438
Other liabilities and accrued expenses	24	25
Total liabilities	1,329	463
Noncontrolling interests	$ 494	$ 189