Asset Retirement Obligations

3 Months Ended

Mar. 31, 2016

Asset Retirement Obligation Disclosure [Abstract]

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:



	Three Months Ended March 31,
(millions)	2016			2015
Asset Retirement Obligations, Beginning Balance	$	989		$	751
Liabilities Incurred	2			10
Liabilities Settled	(8		)	(8		)
Revision of Estimate	5			24
Accretion Expense ⁽¹⁾	12			10
Asset Retirement Obligations, Ending Balance	$	1,000		$	787

⁽¹⁾Accretion expense is included in DD&A expense in the consolidated statements of operations.

For the three months ended March 31, 2016 Liabilities incurred were due to new wells and facilities for onshore US. Liabilities settled primarily related to onshore US property abandonments.

Revisions of estimates relate to changes in cost estimates of $5 million for Equatorial Guinea.

For the three months ended March 31, 2015 Liabilities incurred were due to new wells and facilities and included $4 million for onshore US and $6 million for deepwater Gulf of Mexico. Liabilities settled in 2015 relate primarily to non-core US properties classified as held for sale.

Revisions in estimate for 2015 relate to changes in cost estimates for Eastern Mediterranean.