Securities - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013 security	Mar. 31, 2014 security		Dec. 31, 2013 security
Schedule of Available-for-sale Securities [Line Items]
Securities held-to-maturity		$ 1,285,000,000		$ 1,358,000,000
Temporary impairment losses recognized credit loss	0
Other-than-temporary securities accumulated impairment		101,000,000		104,000,000
Assets backed securities in available for sale portfolio		21		22
Assets backed securities wrapped by monoline insurance company		8		8
Value of asset backed securites backed by insurance company		315,000,000		321,000,000
Fair value of asset backed securities		411,000,000		448,000,000
Available-for-sale securities, accumulated unrecognized holding loss		42,000,000		42,000,000
Fair value of financial guarantee		95,000,000		98,000,000
Security wrapped by below investment grade monoline insurance was deemed to be other-than-temporarily impaired		0		0
Assets backed securities in held for sale portfolio	6
Sold security at carrying value	71,000,000
Gross realized gains on HTM securities	8,000,000
Asset backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities held-to-maturity		180,000,000		200,000,000
Asset backed securities and other debt securities of VIE [Member]
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary securities accumulated impairment		101,000,000	[1]	104,000,000	[1]
Federal Home Loan Bank [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments in stock were included in other assets		139,000,000
Federal Reserve Bank [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments in stock were included in other assets		$ 483,000,000

[1] Relates to securities held by Bryant Park Funding LLC ("Bryant Park"), a variable interest entity which was consolidated in the second quarter of 2013. See Note 16, "Variable Interest Entities" for additional information.