Derivative Instruments - Change in Unrealized Gains (Losses) in AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	$ 268	$ 570	$ 536	$ 684
Balance at end of period	498	402	498	402
Cash Flow Hedging
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(1)	4	2	4
Change in fair value, net of tax	13	(3)	6	1
Reclassification into earnings, net of tax	(2)	0	2	(4)
Balance at end of period	10	1	10	1
Net Investment Hedging
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	0	0	(8)	0
Change in fair value, net of tax	(36)	0	(28)	0
Reclassification into earnings, net of tax	0	0	0	0
Balance at end of period	$ (36)	$ 0	$ (36)	$ 0