ASSET RETIREMENT OBLIGATIONS (Tables)

3 Months Ended

Mar. 31, 2024

Asset Retirement Obligation Disclosure [Abstract]

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 millions	2024		2023
Accretion	$	3.5	$	3.4
Depreciation	2.4		2.2
Total	$	5.9	$	5.6

Reconciliations of Asset Retirement Obligations

Reconciliations of the carrying amounts of our AROs are as follows:

	Three Months Ended March 31
in millions	2024		2023
Balance at beginning of period	$	324.1	$	311.3
Liabilities incurred	0.0		0.0
Liabilities settled	(1.8)		(2.9)
Accretion expense	3.5		3.4
Revisions, net	(0.1)		0.1
Balance at end of period	$	325.7	$	311.9