Securities-Pre-Tax Net Securities Gains (Losses) by Type (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net securities gains	$ 22	$ 39	$ 48
U.S. Treasury
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net securities gains	10	11	(4)
U.S. Government agencies
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net securities gains	7	0	0
Commercial MBS
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net securities gains	0	1	8
State and political subdivisions
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net securities gains	(1)	13	0
Foreign covered bonds
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net securities gains	0	0	8
Non-agency RMBS
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net securities gains	(2)	2	4
European floating rate notes
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net securities gains	(1)	11	4
Other securities
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Net securities gains	$ 9	$ 1	$ 28