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ACCOUNTING POLICIES (Tables)
12 Months Ended
Dec. 31, 2022
Accounting Policies [Abstract]  
Asset retirement obligation activity
The activities of our asset retirement obligations were as follows:
December 31,
20222021
($ in millions)
Beginning balance$70.2 $65.0 
Accretion3.8 3.2 
Spending(8.7)(8.1)
Adjustments1.0 10.1 
Ending balance$66.3 $70.2