Stockholders' Equity - Components of Other Comprehensive Income Loss and Related Tax Impact (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Before Tax
Net unrealized gains (losses) on securities available for sale	$ (393)	$ 482	$ (961)
Net changes in securities held to maturity	151	131	(1,435)
Net unrealized gains (losses) on cash flow hedges	175	192	(250)
Foreign currency translation adjustments	(86)	29	8
Other	(14)	(18)	49
Other comprehensive income before taxes	(167)	816	(2,589)
Provision (Benefit)
Net unrealized (losses) gains on securities available for sale	(145)	178	(364)
Net changes in securities held to maturity	55	55	(538)
Net unrealized gains (losses) on cash flow hedges	65	72	(95)
Foreign currency translation adjustments	49	77	0
Other	(5)	(8)	19
Other comprehensive income (loss), provision (benefit)	19	374	(978)
After Tax
Net unrealized (losses) gains on securities available for sale	(248)	304	(597)
Net changes in securities held to maturity	96	76	(897)
Net unrealized gains (losses) on cash flow hedges	110	120	(155)
Foreign currency translation adjustments	(135)	(48)	8
Other	(9)	(10)	30
Other comprehensive income (loss), net of tax	$ (186)	$ 442	$ (1,611)