Asset Retirement Obligations

6 Months Ended

Jun. 30, 2015

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:



	Six Months Ended June 30,
(millions)	2015			2014
Asset Retirement Obligations, Beginning Balance	$	751		$	586
Liabilities Incurred	16			22
Liabilities Settled	(15		)	(43		)
Revision of Estimate	79			120
Accretion Expense ⁽¹⁾	21			19
Asset Retirement Obligations, Ending Balance	$	852		$	704

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

For the six months ended June 30, 2015

Liabilities incurred were due to new wells and facilities for onshore US and deepwater Gulf of Mexico. Liabilities settled relate primarily to non-core, onshore US properties sold.

Revisions in estimate related to changes in cost estimates and included $43 million for Eastern Mediterranean and $28 million for DJ Basin.

For the six months ended June 30, 2014

Liabilities incurred were due to new wells and facilities for onshore US and Eastern Mediterranean. Liabilities settled primarily related to onshore US property abandonments and non-core, onshore US assets sold.

Revisions in estimate included $67 million for the North Sea McCulloch field due to an increase in costs and a change in timing. See Note 5. Asset Impairments. Additional revisions of $21 million for DJ Basin, $16 million for Equatorial Guinea, $9 million for Eastern Mediterranean, and $7 million for deepwater Gulf of Mexico were due to changes in cost and timing estimates.