ASSET RETIREMENT OBLIGATIONS (Tables)

12 Months Ended

Dec. 31, 2020

Environmental Remediation Obligations [Abstract]

Schedule of Asset Retirement Obligations

The following is a summary of our asset retirement obligations:

	(In Millions)
	December 31,
	2020		2019
Asset retirement obligations1	$	342	$	165
Less: current portion	7		2
Long-term asset retirement obligations	$	335	$	163
1 Includes $190 million and $22 million related to our active operations as of December 31, 2020 and 2019, respectively.

Asset Retirement Obligations

The following is a roll-forward of our asset retirement obligation liability:

	(In Millions)
	2020		2019
Asset retirement obligation as of January 1	$	165	$	172
Increase from acquisitions	172		—
Accretion expense	14		10
Remediation payments	(9)		(1)
Revision in estimated cash flows	—		(16)
Asset retirement obligation as of December 31	$	342	$	165