Mortgage Loan Repurchase Losses (Detail) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Reserve for mortgage loan repurchase losses
Balance at beginning of period	$ 299	$ 256	$ 265	$ 200
Repurchase provision	117	95	287	371
Charge-offs	(134)	(81)	(270)	(301)
Balance at end of period	$ 282	$ 270	$ 282	$ 270