Securities - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2013 security	Dec. 31, 2013 security	Dec. 31, 2012 security
Schedule of Available-for-sale Securities [Line Items]
Securities held-to-maturity		$ 1,358,000,000	$ 1,620,000,000
Temporary impairment losses recognized credit loss		0	0
Other-than-temporary securities accumulated impairment		104,000,000
Non-credit component unrealized loss amounts recognized			0
Assets backed securities in available for sale portfolio		22	27
Assets backed securities wrapped by monoline insurance company		8	8
Value of asset backed securites backed by insurance company		321,000,000	343,000,000
Fair value of asset backed securities		448,000,000	557,000,000
Available-for-sale securities, accumulated unrecognized holding loss		42,000,000	69,000,000
Fair value of financial guarantee		98,000,000	110,000,000
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		200,000,000
Federal Home Loan Bank [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments in stock were included in other assets		139,000,000	143,000,000
Federal Reserve Bank [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments in stock were included in other assets		$ 483,000,000	$ 483,000,000