Consolidated Statements of Comprehensive Income Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax	$ 81	$ (117)	$ 246	$ (64)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	43	(20)	133	7
Credit Risk Adjustment, Tax	0	0	(1)	0
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax	$ 2	$ (2)	$ 37	$ (45)