Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Share-Based Compensation - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
2006 Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock remain authorized for delivery (in shares)	2,700,000
Share-Settled RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of restricted shares vested	$ 15	$ 11	$ 5
Compensation expense	18	$ 13	$ 19
Unrecognized compensation expense	$ 18
Unrecognized compensation expense period	2 years
Directors \| Share-Settled RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restriction period for restricted common stock	3 years
Directors \| Share-Settled PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restriction period for restricted common stock	3 years
Tranche One \| Directors \| Share-Settled RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	33.00%
Tranche Two \| Directors \| Share-Settled RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	33.00%
Tranche Three \| Directors \| Share-Settled RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	33.00%