Commitments, Guarantees, and Contingencies (Contractual Amounts of Credit-Related Off-Balance Sheet Financial Instruments) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
Indemnified securities financing	$ 314,940	$ 302,341
Stable value protection	32,171	33,512
Asset purchase agreements	4,549	5,063
Standby letters of credit	$ 4,565	$ 4,552