Regulatory Assets and Liabilities (Tables) (Alabama Gas Corporation [Member])

9 Months Ended

Sep. 30, 2012

Alabama Gas Corporation [Member]

Regulatory Assets and Liabilities [Line Items]

Schedule of Regulatory Assets and Liabilities [Table Text Block]

The following table details regulatory assets and liabilities on the balance sheets:

(in thousands)	September 30, 2012				December 31, 2011
	Current		Noncurrent		Current		Noncurrent
Regulatory assets:
Pension and postretirement assets	$	170	$	79,984	$	170	$	77,587
Accretion and depreciation for asset retirement obligation	—		14,885		—		13,981
Risk management activities	14,990		—		56,804		3,070
Asset removal costs, net	—		—		—		994
Gas supply adjustment	40,998		—		—		—
Other	30		—		169		1
Total regulatory assets	$	56,188	$	94,869	$	57,143	$	95,633
Regulatory liabilities:
RSE adjustment	$	3,187	$	—	$	2,931	$	—
Unbilled service margin	5,799		—		22,419		—
Gas supply adjustment	—		—		12,626		—
Refundable negative salvage	18,353		55,389		20,269		65,646
Asset retirement obligation	—		21,525		—		20,785
Other	33		778		34		803
Total regulatory liabilities	$	27,372	$	77,692	$	58,279	$	87,234