Guarantee Arrangements and Pledged Assets and Collateral - Additional Information (Detail) (USD $)							36 Months Ended						3 Months Ended
	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2007 Hsbc Securities [Member]	Jun. 30, 2014 Securities available-for-sale [Member]	Dec. 31, 2013 Securities available-for-sale [Member]	Jun. 30, 2014 Trading Securities [Member]	Dec. 31, 2013 Trading Securities [Member]	Jun. 30, 2014 Financial Guarantee [Member] Collateralized Securities [Member]	Dec. 31, 2013 Federal National Mortgage Association [Member]	Mar. 31, 2014 Federal Home Loan Mortgage Corporation [Member]
Guarantor Obligations [Line Items]
Deferred fee on stand by letters of credit	$ 41,000,000		$ 46,000,000
Allowance for credit losses on unfunded standby letters of credit	19,000,000		18,000,000
Settlement with FNMA													83,000,000	25,000,000
Release of provision													15,000,000	34,000,000
Outstanding repurchase demands on loans sourced from our legacy broker channel	1,000,000		26,000,000
Repurchase liability for loans	34,000,000	36,000,000	99,000,000	217,000,000	211,000,000	219,000,000
Range of possible losses in excess of recorded repurchase liability, minimum												0
Range of possible losses in excess of recorded repurchase liability, maximum												30,000,000
Liquidity facilities	2,354,000,000		2,560,000,000
Securities available-for-sale								5,342,000,000	10,950,000,000	3,051,000,000	1,296,000,000
Separately reported available-for-sale pledged assets	7,345,000,000		4,187,000,000
Securities sold under agreements to repurchase	3,522,000,000		2,771,000,000
Whole loan securitization							$ 24,000,000,000