Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net Income	$ 575	$ 452	$ 1,139	$ 864
Change in net unrealized gain (loss) on available for sale securities:
Net unrealized gain (loss)	29	168	81	189
Reclassification of net unrealized loss transferred to held to maturity	0	0	227	0
Other reclassifications included in other revenue	(6)	(3)	(7)	(3)
Change in net unrealized gain (loss) on held to maturity securities:
Reclassification of net unrealized loss transferred from available for sale	0	0	(227)	0
Amortization of amounts previously recorded upon transfer from available for sale	9	0	11	0
Other	0	0	(3)	1
Other comprehensive income (loss), before tax	32	165	82	187
Income tax effect	(12)	(62)	(31)	(70)
Other comprehensive income (loss), net of tax	20	103	51	117
Comprehensive Income	$ 595	$ 555	$ 1,190	$ 981