Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 207	$ 145	$ 227	$ 425
Net changes in cash flow hedges, net of taxes	23	(44)	(203)	(237)
Total comprehensive income (loss)	$ 230	$ 101	$ 24	$ 188