Fair Value Option (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Changes in fair value under the fair value option election
Federal funds sold and securities purchased under resale agreements	$ 161	$ 270	$ 173
Securities borrowed	10	(61)	31
Trading assets:
Debt and equity instruments, excluding loans	520	47	554
Loans reported as trading assets:
Changes in instrument-specific credit risk	1,570	760	1,273
Other changes in fair value	7,487	5,390	4,137
Loans:
Fair Value, Option, Credit Risk, Gains (Losses) on Assets	(14)	2	95
Other changes in fair value	676	535	90
Other assets	(339)	(68)	(263)
Deposits	(188)	(237)	(564)
Federal funds purchased and securities loaned or sold under repurchase agreements	(25)	(4)	(29)
Other borrowed funds	494	2,986	123
Trading liabilities	(41)	(57)	(23)
Beneficial interests issued by consolidated VIEs	(166)	(83)	(12)
Other liabilities	0	(8)	(1)
Long-term debt:
Changes in instrument-specific credit risk related to structured notes	(835)	927	400
Other changes in fair value	(1,025)	322	1,297
Debit Valuation Adjustment [Member]
Long-term debt:
Changes in instrument-specific credit risk related to structured notes	(340)	899	468
Principal transactions
Changes in fair value under the fair value option election
Federal funds sold and securities purchased under resale agreements	161	270	173
Securities borrowed	10	(61)	31
Trading assets:
Debt and equity instruments, excluding loans	513	53	556
Loans reported as trading assets:
Changes in instrument-specific credit risk	1,489	934	1,279
Other changes in fair value	(183)	127	(312)
Loans:
Fair Value, Option, Credit Risk, Gains (Losses) on Assets	(14)	2	95
Other changes in fair value	676	535	90
Other assets	0	(49)	0
Deposits	(188)	(237)	(564)
Federal funds purchased and securities loaned or sold under repurchase agreements	(25)	(4)	(29)
Other borrowed funds	494	2,986	123
Trading liabilities	(41)	(57)	(23)
Beneficial interests issued by consolidated VIEs	(166)	(83)	(12)
Other liabilities	0	(3)	(9)
Long-term debt:
Changes in instrument-specific credit risk related to structured notes	(835)	927	400
Other changes in fair value	(1,025)	322	1,297
Other income
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	(6)	(2)
Loans reported as trading assets:
Changes in instrument-specific credit risk	81	(174)	(6)
Other changes in fair value	7,670	5,263	4,449
Loans:
Fair Value, Option, Credit Risk, Gains (Losses) on Assets	0	0	0
Other changes in fair value	0	0	0
Other assets	(339)	(19)	(263)
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	0	(5)	8
Long-term debt:
Changes in instrument-specific credit risk related to structured notes	0	0	0
Other changes in fair value	$ 0	$ 0	$ 0