Stockholders' Equity - Components of Other Comprehensive Income Loss and Related Tax Impact (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Before Tax
Net unrealized gains (losses) on securities available for sale	$ (605)	$ 23	$ (254)
Net changes in securities held to maturity	588	150	164
Net unrealized gains (losses) on cash flow hedges	(98)	(325)	(315)
Foreign currency translation adjustments	9	3	86
Other	(15)	38	10
Other comprehensive income before taxes	(121)	(111)	(309)
Provision (Benefit)
Net unrealized gains (losses) on securities available for sale	(146)	2	(88)
Net changes in securities held to maturity	141	53	60
Net unrealized losses on cash flow hedges	(24)	(122)	(117)
Foreign currency translation adjustments	48	(81)	165
Other	(4)	14	4
Other comprehensive income (loss), provision (benefit)	15	(134)	24
After Tax
Net unrealized gains (losses) on securities available for sale	(459)	21	(166)
Net changes in securities held to maturity	447	97	104
Net unrealized losses on cash flow hedges	(74)	(203)	(198)
Foreign currency translation adjustments	(39)	84	(79)
Other	(11)	24	6
Other comprehensive income (loss), net of tax	$ (136)	$ 23	$ (333)

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