v3.25.2
ASSET RETIREMENT OBLIGATIONS (Tables)
 6 Months Ended
Jun. 30, 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
June 30		Six Months Ended
June 30
in millions2025202420252024
Accretion$4.8 $3.6 $9.0 $7.1 
Depreciation4.0 2.8 8.0 5.2 
Total ARO operating costs$8.8 $6.4 $17.0 $12.3 
Schedule of Reconciliations of Asset Retirement Obligations
Reconciliations of the carrying amounts of our ARO liabilities are as follows:
Three Months Ended
June 30		Six Months Ended
June 30
in millions2025202420252024
ARO liability balance at beginning of period$429.5 $325.7 $427.4 $324.1 
Liabilities incurred18.2 0.8 23.2 0.8 
Liabilities settled 1
(4.7)(3.0)(11.6)(4.8)
Accretion expense4.8 3.6 9.0 7.1 
Revisions, net
0.0 7.0 (0.2)6.9 
ARO liability balance at end of period$447.8 $334.1 $447.8 $334.1