Long-Term Debt - Interest Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Gross interest expense	$ 376	$ 416	$ 517
Capitalized interest	(15)	(23)	(15)
Total interest expense	$ 361	$ 393	$ 502