Consolidated Statements of Comprehensive Income Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net Income (Loss) Attributable to Parent	$ 623	$ 752	$ 1,891	$ 2,117
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax	166	(178)	960	(726)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	82	(20)	302	(179)
Other Comprehensive Income (Loss), Brokered Time Deposits, Net of Tax	0	0	(1)	0
Other Comprehensive Income (Loss), Long Term Debt, Adjustment, Net of Tax	0	0	0	3
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	4	3	10	2
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	252	(195)	1,271	(900)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 875	$ 557	$ 3,162	$ 1,217