Stockholders' Equity - Components of Other Comprehensive Income Loss and Related Tax Impact (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Before Tax
Net unrealized gains (losses) on securities available for sale	$ 237	$ 212	$ 283	$ 508
Net changes in securities held to maturity	37	41	73	74
Net unrealized gains (losses) on cash flow hedges	72	227	(32)	827
Foreign currency translation adjustments	(3)	40	1	66
Other	5	12	12	(5)
Other comprehensive income before taxes	348	532	337	1,470
Provision (Benefit)
Net unrealized gains on securities available for sale	88	76	98	185
Net changes in securities held to maturity	14	16	27	28
Net unrealized gains (losses) on cash flow hedges	27	84	(11)	307
Foreign currency translation adjustments	(34)	70	(47)	95
Other	2	4	4	(2)
Other comprehensive income (loss), provision (benefit)	97	250	71	613
After Tax
Net unrealized gains on securities available for sale	149	136	185	323
Net changes in securities held to maturity	23	25	46	46
Net unrealized gains (losses) on cash flow hedges	45	143	(21)	520
Foreign currency translation adjustments	31	(30)	48	(29)
Other	3	8	8	(3)
Other comprehensive income (loss), net of tax	$ 251	$ 282	$ 266	$ 857

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