Stockholders' Equity - Fair Value of Awards Granted and Vested (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted shares granted	$ 65	$ 67	$ 53
Fair value of restricted shares vested	124	23	21
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted shares granted	65	44	33
Fair value of restricted shares vested	53	22	19
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted shares granted	0	23	20
Fair value of restricted shares vested	$ 71	$ 1	$ 2