Consolidated Statement of Comprehensive Income Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 1,715	$ 1,263	$ 929
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent [Abstract]
Other comprehensive income (loss), investment securities, net unrealized gains (losses) arising during the period, after tax	741	(287)	192
Other comprehensive income (loss), investment securities, net realized gains reclassified to income from continuing operations, after tax	60	8	92
Other comprehensive income (loss), investment securities, net change, after tax	681	(295)	100
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Other comprehensive income (loss), translation adjustments, net unrealized gains (losses) arising during the period, after tax	5	(11)	8
Other Comprehensive Income (loss), net investment hedges, net unrealized gains (losses) arising during the period	(4)	9	(6)
Other comprehensive income (loss), translation adjustments and net investment hedges, net change	1	(2)	2
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Other comprehensive income (loss), cash flow hedges, net unrealized gains (losses) arising during the period	(7)	10	3
Other comprehensive income (loss), cash flow hedge, gain (loss), reclassification, after tax	10	2	0
Other comprehensive income (loss), cash flow hedge, gain (loss), after reclassification and tax	(17)	8	3
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax [Abstract]
Other comprehensive (income) loss, defined benefit plan, after reclassification adjustment, after tax	(11)	0	1
Other Comprehensive Income (Loss), net of tax	654	(289)	106
Comprehensive Income	$ 2,369	$ 974	$ 1,035