Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Unrealized holding gain (loss) on securities, tax	$ 1	$ (5)	$ (10)	$ (5)
Reclassification adjustment on sale of securities, tax	2	0	3	0
Unrealized gain (loss) on derivatives, tax	0	2	23	2
Reclassification adjustment on derivatives, tax	$ (2)	$ 0	$ (6)	$ 0