Asset Quality (Details 11) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2012	Dec. 31, 2011
Changes in the liability for credit losses on lending-related commitments
Beginning Balance	$ 73	$ 45	$ 45
Provision (credit) for losses on lending-related commitments	(4)
Ending Balance	$ 69	$ 45	$ 45