Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 1,447	$ 1,321	$ 1,071
Change in net unrealized gain on securities available for sale:
Net unrealized gain (loss)	(477)	255	(468)
Reclassification of impairment charges included in net impairment losses on securities		1	10
Other reclassifications included in other revenue		(7)	(7)
Other			1
Other comprehensive income (loss), before tax	(477)	249	(464)
Income tax effect	178	(93)	175
Other comprehensive income (loss), net of tax	(299)	156	(289)
Comprehensive Income	$ 1,148	$ 1,477	$ 782