REGULATORY ASSETS AND LIABILITIES (Tables)

3 Months Ended

Mar. 31, 2013

Regulatory Assets and Liabilities Disclosure [Abstract]

Schedule of Regulatory Assets

Regulatory Assets consisted of the following items (in thousands):

	March 31, 2013		December 31, 2012
Environmental Remediation Costs:
Expended - Net	$	32,784	$	37,892
Liability for Future Expenditures	108,013		107,410
Deferred Asset Retirement Obligation Costs	30,390		30,199
Deferred Pension and Other Postretirement Benefit Costs	95,897		95,897
Conservation Incentive Program Receivable	18,629		31,686
Societal Benefit Costs Receivable	12,900		12,801
Premium for Early Retirement of Debt	1,035		1,075
Deferred Interest Rate Contracts (Note 11)	6,885		7,761
Energy Efficiency Tracker	12,556		12,306
Pipeline Supplier Service Charges	8,355		8,771
Other Regulatory Assets	7,645		6,858
Total Regulatory Assets	$	335,089	$	352,656

Schedule of Regulatory Liabilities

Regulatory Liabilities consisted of the following items (in thousands):

	March 31, 2013		December 31, 2012
Excess Plant Removal Costs	$	43,567	$	45,593
Deferred Revenues-Net	27,533		10,924
Other Regulatory Liabilities	2,498		—
Total Regulatory Liabilities	$	73,598	$	56,517