Variable Interest Entities - Loans Sold to Third-Party Sponsored Securitization Entities (Details 5) (Variable Interest Entity, Not Primary Beneficiary [Member], USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Variable Interest Entity, Not Primary Beneficiary [Member]
Summary of loan sale activities [Abstract]
Carrying value of loans sold	$ 39,959,000,000	$ 39,247,000,000
Proceeds received from loan sales as cash	548,000,000	340,000,000
Proceeds received from loan sales as securities	38,874,000,000	38,172,000,000
Total proceeds received from loan sales	39,422,000,000	38,512,000,000
Gains on loan sales	35,000,000	22,000,000
Loans Repurchased Or Loans With The Option To Repurchase	15,900,000,000		15,700,000,000
Real Estate Acquired Through Foreclosure	$ 1,200,000,000		$ 1,000,000,000