Asset Retirement Obligations

3 Months Ended

Mar. 31, 2012

Asset Retirement Obligations [Abstract]

Asset Retirement Obligations

Note 8.  Asset Retirement Obligations

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

	Three Months Ended March 31,
	2012			2011
(millions)
Asset Retirement Obligations, Beginning Balance	$	377		$	253
Liabilities Incurred		6			1
Liabilities Settled		(2	)		(9	)
Revision of Estimate		3			4
Accretion Expense		7			5
Asset Retirement Obligations, Ending Balance	$	391		$	254

Liabilities settled in 2011 related primarily to Deepwater Gulf of Mexico and Gulf of Mexico shelf properties.

Accretion expense is included in depreciation, depletion and amortization (DD&A)expense in the consolidated statements ofoperations.