Consolidated Statements of Comprehensive Income Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax	$ 127	$ (38)	$ 243	$ (168)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	43	(10)	67	(49)
Other Comprehensive Income (Loss), Brokered Time Deposits, Tax	0	0	0	0
Other Comprehensive Income (Loss), Long Term Debt, Adjustment, Tax	0	0	0	1
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	$ 1	$ 0	$ 3	$ 1