Stockholders' Equity - Components of Other Comprehensive Income Loss and Related Tax Impact (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Before Tax
Net unrealized gains (losses) on securities available for sale	$ 98	$ (104)	$ 29	$ 394
Net changes in securities held to maturity	41	35	114	96
Net unrealized gains (losses) on cash flow hedges	365	(107)	494	37
Foreign currency translation adjustments	(15)	(41)	(77)	25
Other	(15)	6	(19)	2
Other comprehensive income before taxes	474	(211)	541	554
Provision (Benefit)
Net unrealized gains on securities available for sale	36	(39)	11	146
Net changes in securities held to maturity	16	13	42	40
Net unrealized gains on cash flow hedges	135	(39)	183	15
Foreign currency translation adjustments	37	41	24	41
Other	(5)	1	(7)	(1)
Other comprehensive income (loss), provision (benefit)	219	(23)	253	241
After Tax
Net unrealized gains on securities available for sale	62	(65)	18	248
Net changes in securities held to maturity	25	22	72	56
Net unrealized gains on cash flow hedges	230	(68)	311	22
Foreign currency translation adjustments	(52)	(82)	(101)	(16)
Other	(10)	5	(12)	3
Other comprehensive income (loss), net of tax	$ 255	$ (188)	$ 288	$ 313