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Property, Plant and Equipment - Asset Retirement Obligations (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]      
Balance at beginning of period $ 122 $ 113 $ 105
Accretion expense 5 6 5
Liabilities settled (10) (7) (12)
Revision in estimated cash flows 7 10 15
Reclassified as held for sale (3) 0 0
Balance at end of period $ 121 $ 122 $ 113