Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 167	$ 199
Accumulated Amortization	(151)	(180)
Net Carrying Amount	16	19
Core Deposits
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	122	154
Accumulated Amortization	(111)	(141)
Net Carrying Amount	11	13
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	45	45
Accumulated Amortization	(40)	(39)
Net Carrying Amount	$ 5	$ 6