Fair Value Option - Aggregate Differences (Details 1) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Long-term debt
Long-term debt	$ 268,361	$ 249,024
Carrying value
Loans
Nonaccrual loans	5,150	4,333
Total loans	47,131	50,628
Carrying value | Trading assets
Loans
Nonaccrual loans	5,062	4,217
All other performing loans	40,151	44,084
Carrying value | Total loans
Loans
Nonaccrual loans	88	116
All other performing loans	1,830	2,211
Carrying value | Principal Protected Debt
Long-term debt
Long-term debt	16,629	16,541
Fair value
Loans
Nonaccrual loans	1,363	1,024
Total loans	40,280	43,704
Long-term debt
Long-term debt	30,655	30,788
Long-term beneficial interests
Total long-term beneficial interests	1,130	1,170
Fair value | Trading assets
Loans
Nonaccrual loans	1,302	960
All other performing loans	37,203	40,581
Fair value | Total loans
Loans
Nonaccrual loans	61	64
All other performing loans	1,714	2,099
Fair value | Principal Protected Debt
Long-term debt
Long-term debt	16,607	16,391
Fair value | Non Principal Protected Debt
Long-term debt
Long-term debt	14,048	14,397
Long-term beneficial interests
Total long-term beneficial interests	1,130	1,170
Change During Period, Fair Value Disclosure
Loans
Nonaccrual loans	(3,787)	(3,309)
Total loans	(6,851)	(6,924)
Change During Period, Fair Value Disclosure | Trading assets
Loans
Nonaccrual loans	(3,760)	(3,257)
All other performing loans	(2,948)	(3,503)
Change During Period, Fair Value Disclosure | Total loans
Loans
Nonaccrual loans	(27)	(52)
All other performing loans	(116)	(112)
Change During Period, Fair Value Disclosure | Principal Protected Debt
Long-term debt
Long-term debt	$ (22)	$ (150)