Asset Retirement Obligations

6 Months Ended

Jun. 30, 2020

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligations

Note 7. Asset Retirement Obligations

Asset retirement obligations (ARO) consist primarily of estimated costs of dismantlement, removal, site reclamation and similar activities associated with our oil and gas properties. Changes in ARO are as follows:

	Six Months Ended June 30,
(millions)	2020			2019
Asset Retirement Obligations, Beginning Balance	$	814		$	880
Liabilities Incurred	19			15
Liabilities Settled	(42		)	(56		)
Revisions of Estimates	9			(70		)
Accretion Expense	21			23
Asset Retirement Obligations, Ending Balance	$	821		$	792

Six Months Ended June 30, 2020 Liabilities incurred primarily relate to properties in Israel and the DJ Basin. Liabilities settled primarily relate to abandonment of US onshore properties, with $35 million in the DJ Basin where we have engaged in a program to plug and abandon older vertical wells. Costs associated with these abandonment activities will be incurred over several years. The revision of estimates is due to changes in both timing of spend and cost in the DJ Basin.

Six Months Ended June 30, 2019 Liabilities settled relate to abandonment of US onshore properties, primarily in the DJ Basin where we have engaged in a program to plug and abandon older vertical wells. Costs associated with these abandonment activities will be incurred over several years. Revisions of estimates primarily relate to a decrease of $73 million in the DJ Basin as a result of improved cycle times and cost reductions for vertical wells.