Fair Value Option - Changes in fair value under the fair value option (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Changes in fair value under the fair value option election
Federal funds sold and securities purchased under resale agreements	$ (454)	$ 161	$ 270
Securities borrowed	10	10	(61)
Trading assets:
Debt and equity instruments, excluding loans	589	520	47
Loans reported as trading assets:
Changes in instrument-specific credit risk	1,184	1,570	760
Other changes in fair value	1,700	7,487	5,390
Loans:
Changes in instrument-specific credit risk	36	(14)	2
Other changes in fair value	17	676	535
Other assets	3	(339)	(68)
Deposits	260	(188)	(237)
Federal funds purchased and securities loaned or sold under repurchase agreements	73	(25)	(4)
Other borrowed funds	(399)	494	2,986
Trading liabilities	(46)	(41)	(57)
Beneficial interests issued by consolidated VIEs	(278)	(166)	(83)
Other liabilities	2	0	(8)
Long-term debt:
Changes in instrument-specific credit risk related to structured notes	(271)	(835)	927
Other changes in fair value	1,280	(1,025)	322
Debit valuation adjustment [Member]
Long-term debt:
Changes in instrument-specific credit risk related to structured notes	(337)	(340)	899
Principal transactions [Member]
Changes in fair value under the fair value option election
Federal funds sold and securities purchased under resale agreements	(454)	161	270
Securities borrowed	10	10	(61)
Trading assets:
Debt and equity instruments, excluding loans	582	513	53
Loans reported as trading assets:
Changes in instrument-specific credit risk	1,161	1,489	934
Other changes in fair value	(133)	(183)	127
Loans:
Changes in instrument-specific credit risk	36	(14)	2
Other changes in fair value	17	676	535
Other assets	32	0	(49)
Deposits	260	(188)	(237)
Federal funds purchased and securities loaned or sold under repurchase agreements	73	(25)	(4)
Other borrowed funds	(399)	494	2,986
Trading liabilities	(46)	(41)	(57)
Beneficial interests issued by consolidated VIEs	(278)	(166)	(83)
Other liabilities	0	0	(3)
Long-term debt:
Changes in instrument-specific credit risk related to structured notes	(271)	(835)	927
Other changes in fair value	1,280	(1,025)	322
Other income [Member]
Changes in fair value under the fair value option election
Federal funds sold and securities purchased under resale agreements	0	0	0
Securities borrowed	0	0	0
Trading assets:
Debt and equity instruments, excluding loans	7	7	(6)
Loans reported as trading assets:
Changes in instrument-specific credit risk	23	81	(174)
Other changes in fair value	1,833	7,670	5,263
Loans:
Changes in instrument-specific credit risk	0	0	0
Other changes in fair value	0	0	0
Other assets	(29)	(339)	(19)
Deposits	0	0	0
Federal funds purchased and securities loaned or sold under repurchase agreements	0	0	0
Other borrowed funds	0	0	0
Trading liabilities	0	0	0
Beneficial interests issued by consolidated VIEs	0	0	0
Other liabilities	2	0	(5)
Long-term debt:
Changes in instrument-specific credit risk related to structured notes	0	0	0
Other changes in fair value	$ 0	$ 0	$ 0