Mortgage Loan Repurchase Losses (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Reserve for mortgage loan repurchase losses
Balance at beginning of period	$ 83	$ 513	$ 78	$ 632
Repurchase provision	5	15	10	29
Charge-offs	(11)	(165)	(11)	(298)
Balance at end of period	$ 77	$ 363	$ 77	$ 363