Asset Retirement Obligations Asset Retirement Obligations (Tables)

6 Months Ended

Jun. 30, 2013

Asset Retirement Obligation Disclosure [Abstract]

Schedule of Change in Asset Retirement Obligation [Table Text Block]

The following summarizes the changes in asset retirement obligations during the first six months of 2013:

(In millions)
Beginning balance	$	1,783
Incurred, including acquisitions	8
Settled, including dispositions	(27		)
Accretion expense (included in depreciation, depletion and amortization)	48
Revisions to previous estimates	306
Held for sale	(39		)
Ending balance(a)	$	2,079

^(a) Includes asset retirement obligations of $40 million classified as a short-term at June 30,2013.