Accounting for Asset Retirement Obligations (Tables)

3 Months Ended

Mar. 31, 2019

Accounting for Asset Retirement Obligations [Abstract]

Reconciliation of Asset Retirement Obligations

The following is a reconciliation of asset retirement obligations as of March 31, 2019:

(millions of dollars)
Asset retirement liability, December 31, 2018	$	23.4
Accretion expense		0.9
Payments		(0.7	)
Asset retirement liability, March 31, 2019	$	23.6