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Asset Retirement Obligations (Tables)
12 Months Ended
Dec. 31, 2021
Asset Retirement Obligation Disclosure [Abstract]  
Schedule of changes in asset retirement obligations The reconciliation of the changes in our AROs is presented below:
 Year ended December 31,
 20212020
Beginning balance, ARO liability$19.8 $18.9 
Additional ARO liability incurred4.9 2.3 
ARO liabilities settled(6.1)(2.2)
Accretion expense2.1 1.3 
Revisions in estimated cash flows— (0.5)
Ending balance, ARO liability$20.7 $19.8