Asset Retirement Obligations

6 Months Ended

Jun. 30, 2014

Asset Retirement Obligation Disclosure [Abstract]

ARO consists 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)	2014			2013
Asset Retirement Obligations, Beginning Balance	$	586		$	402
Liabilities Incurred	22			2
Liabilities Settled	(43		)	(10		)
Revision of Estimate	120			7
Accretion Expense ⁽¹⁾	19			14
Asset Retirement Obligations, Ending Balance	$	704		$	415

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

For the six months ended June 30, 2014

Liabilities incurred were due to new wells and facilities and included $13 million for onshore US and $9 million for Eastern Mediterranean.

Liabilities settled primarily related to onshore US property abandonments and non-core, onshore US assets sold.

Revisions were primarily due to an increase of $67 million related to a non-operated North Sea field due to an increase in costs and a change in timing recorded during the first quarter of 2014. See Note 4. Asset Impairments. Additional revisions were due to changes in cost and timing estimates and primarily included $21 million for DJ Basin, $16 million for Equatorial Guinea, $9 million for Eastern Mediterranean, and $7 million for deepwater Gulf of Mexico.

For the six months ended June 30, 2013

Liabilities incurred were due to new wells and facilities for onshore development. Liabilities settled in 2013 relate primarily to non-core onshore US properties that were sold. See Note 3. Divestitures.