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ASSET RETIREMENT OBLIGATIONS (Tables)
 3 Months Ended
Mar. 31, 2025
Asset Retirement Obligation Disclosure [Abstract]  
Schedule of Asset Retirement Obligations Operating Costs
ARO operating costs related to accretion of the liabilities and depreciation of the assets are as follows:
Three Months Ended
March 31
in millions20252024
Accretion$4.3 $3.5 
Depreciation3.9 2.4 
Total ARO operating costs$8.2 $5.9 
Schedule of Reconciliations of Asset Retirement Obligations
Reconciliations of the carrying amounts of our ARO liabilities are as follows:
Three Months Ended
March 31
in millions20252024
ARO liability balance at beginning of period$427.4 $324.1 
Liabilities incurred0.0 0.0 
Liabilities settled(5.9)(1.8)
Accretion expense4.3 3.5 
Revisions, net3.7 (0.1)
ARO liability balance at end of period$429.5 $325.7