Asset Retirement Obligations

9 Months Ended

Sep. 30, 2011

Notes to Financial Statements [Abstract]

Note 9. 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:

	Nine Months Ended September 30,
	2011			2010
(millions)
Asset Retirement Obligations, Beginning Balance	$	253		$	232
Liabilities Incurred		2			14
Liabilities Settled		(19	)		(35	)
Revision of Estimate		9			11
Accretion Expense		15			13
Asset Retirement Obligations, Ending Balance	$	260		$	235

Liabilities settled in 2011 related primarily to deepwater and shelf properties in the Gulf of Mexico. Liabilities settled in 2010 related to US onshore assets sold and a Gulf of Mexico shelf asset.

Liabilities incurred in 2010 were due primarily to the Central DJ Basin asset acquisition.

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