Stockholders' Equity - Components of Other Comprehensive Income Loss and Related Tax Impact (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Before Tax
Net unrealized gains (losses) on securities available for sale	$ (254)	$ (393)	$ 482
Net changes in securities held to maturity	164	151	131
Net unrealized gains (losses) on cash flow hedges	(315)	175	192
Foreign currency translation adjustments	86	(86)	29
Other	10	(14)	(18)
Other comprehensive income before taxes	(309)	(167)	816
Provision (Benefit)
Net unrealized gains (losses) on securities available for sale	(88)	(145)	178
Net changes in securities held to maturity	60	55	55
Net unrealized gains (losses) on cash flow hedges	(117)	65	72
Foreign currency translation adjustments	165	49	77
Other	4	(5)	(8)
Other comprehensive income (loss), provision (benefit)	24	19	374
After Tax
Net unrealized gains (losses) on securities available for sale	(166)	(248)	304
Net changes in securities held to maturity	104	96	76
Net unrealized gains (losses) on cash flow hedges	(198)	110	120
Foreign currency translation adjustments	(79)	(135)	(48)
Other	6	(9)	(10)
Other comprehensive income (loss), net of tax	$ (333)	$ (186)	$ 442