The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement 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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Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

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Amount of asset retirement obligations incurred during the period.

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Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The amount for the individual regulatory current liability as itemized in a table of regulatory current liabilities as of the end of the period.

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The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent liabilities as of the end of the period.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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Asset Retirement Obligations (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended
Asset Retirement Obligations (Details) (USD $) In Thousands	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance of ARO, beginning			$ 97,415
Liabilities incurred			3,761
Liabilities settled			(1,531)
Accretion expense	1,728	1,561	5,066	4,568
Balance of ARO, end	104,711		104,711
Regulatory Liability, Current	51,849		51,849		75,703
Regulatory Liability, Noncurrent	87,579		87,579		110,447
Alabama Gas Corporation \| Asset removal costs
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Regulatory Liability, Current	0		0		0
Regulatory Liability, Noncurrent	7,834		7,834		6,913
Alabama Gas Corporation \| Refundable negative salvage
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Regulatory Liability, Current	20,545		20,545		22,336
Regulatory Liability, Noncurrent	67,237		67,237		90,504
Refundable negative salvage
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Regulatory Liability, Current	20,545		20,545
Regulatory Liability, Noncurrent	67,237		67,237
Alabama Gas Corporation
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance of ARO, beginning					11,400
Balance of ARO, end	11,700		11,700		11,400
Regulatory Liability, Current	51,849		51,849		75,703
Regulatory Liability, Noncurrent	$ 87,579		$ 87,579		$ 110,447