Consolidated Statements of Comprehensive Income Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax	$ (117)	$ 29	$ (117)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	(21)	0	(145)
Other Comprehensive Income (Loss), Brokered Time Deposits, Tax	0	0	0
Other Comprehensive Income (Loss), Long Term Debt, Adjustment, Tax	1	3	(1)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	$ 1	$ 138	$ 52