Regulatory Assets and Liabilities

9 Months Ended

Sep. 30, 2011

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory Assets and Liabilities

REGULATORY ASSETS AND LIABILITIES

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

(in thousands)	September 30, 2011				December 31, 2010
	Current		Noncurrent		Current		Noncurrent
Regulatory assets:
Pension and postretirement assets	$	170	$	87,181	$	132	$	60,284
Accretion and depreciation for asset retirement obligation	—		9,007		—		8,681
Risk management activities	44,137		13,050		27,906		32,461
RSE adjustment	25		—		25		—
Enhanced stability reserve	—		—		—		3,794
Other	193		6		223		145
Total regulatory assets	$	44,525	$	109,244	$	28,286	$	105,365
Regulatory liabilities:
RSE adjustment	$	5,068	$	—	$	4,147	$	—
Unbilled service margin	5,143		—		34,197		—
Postretirement liabilities	—		—		—		754
Gas supply adjustment	21,060		—		14,990		—
Asset removal costs, net	—		7,834		—		6,913
Refundable negative salvage	20,545		67,237		22,336		90,504
Asset retirement obligation	—		11,697		—		11,439
Other	33		811		33		837
Total regulatory liabilities	$	51,849	$	87,579	$	75,703	$	110,447