Asset Retirement Obligations

6 Months Ended

Jun. 30, 2021

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligations

15. Asset Retirement Obligations

We recognize asset retirement obligations for the removal and disposal of residues; dismantling of certain tanks required by governmental authorities; cleaning and dismantling costs for owned railcars; cleaning costs for leased rail cars and barges; and site demolition, when required by governmental authorities or by contract. The following table reflects changes in the carrying values of asset retirement obligations:

	June 30, 2021			December 31, 2020
(Dollars in millions)
Asset retirement obligation at beginning of year	$	19.8		$	20.7
Accretion expense		0.5			1.1
Revision in estimated cash flows		(2.0	)		4.6
Cash expenditures		(6.1	)		(6.6	)
Balance at end of period	$	12.2		$	19.8