Guarantee Arrangements and Pledged Assets and Collateral - Summary of Change in Estimated Repurchase Liability for Loans Sold to GSEs and Other Third Parties (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Estimated Repurchase Liability For Loans Sold [Roll Forward]
Balance at beginning of period	$ 219	$ 237	$ 262
Increase in liability recorded through earnings	21	134	92
Realized losses	(141)	(152)	(117)
Balance at end of period	$ 99	$ 219	$ 237