Asset Retirement Obligations

3 Months Ended

Mar. 31, 2013

Asset Retirement Obligation Disclosure [Abstract]

Asset retirement obligation (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:



	Three Months Ended March 31,
	2013			2012
(millions)
Asset Retirement Obligations, Beginning Balance	$	402		$	377
Liabilities Incurred	1			6
Liabilities Settled	(10		)	(2		)
Revision of Estimate	(1		)	3
Accretion Expense ⁽¹⁾	7			7
Asset Retirement Obligations, Ending Balance	$	399		$	391

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

Liabilities settled in 2013 relate primarily to onshore US properties sold. See Note 3. Divestitures.

- Definition

The entire disclosure for an asset retirement obligation and the associated long-lived asset. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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