Derivative Instruments - Change in Unrealized Gains (Losses) in AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	$ 536	$ 684
Balance at end of period	(194)	388
Cash Flow Hedging
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	2	3
Change in fair value, net of tax	(9)	6
Reclassification into earnings, net of tax	2	(2)
Balance at end of period	(5)	7
Net Investment Hedging
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(8)	0
Change in fair value, net of tax	24	0
Reclassification into earnings, net of tax	0	0
Balance at end of period	$ 16	$ 0