Condensed Financial Information of Parent - Condensed Statement of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net cash used in operating activities	$ (131)	$ 2,178	$ 385
Cash flows from investing activities:
Net cash provided by (used in) investing activities	(524)	177	(2)
Cash flows from financing activities:
Repurchase of restricted stock shares for payroll tax withholding requirements	(5)	(1)	(1)
Net cash provided by financing activities	(514)	(895)	(363)
Net change in cash and cash equivalents	(1,169)	1,460	20
Cash and cash equivalents at beginning of period	507	1,676	216	$ 196
Parent Company
Cash flows from operating activities:
Net cash used in operating activities	(11)	(12)	(4)
Cash flows from financing activities:
Repurchase of restricted stock shares for payroll tax withholding requirements	(5)	(1)	(1)
Changes in intercompany balances with affiliates, net	16	13	5
Net cash provided by financing activities	$ 11	$ 12	$ 4