CONSOLIDATED BALANCE SHEETS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets
Cash and cash equivalents	$ 6,357	$ 3,763
Accounts receivable, net	282,685	317,039
Accounts receivable from affiliates	15,421	12,063
Investments in utility money pool arrangement	72,000	52,000
Accrued unbilled revenues	192,394	304,544
Inventories	197,161	253,997
Regulatory assets	125,876	196,311
Deferred income taxes	24,719	33,349
Derivative instruments	5,357	4,930
Prepayments and other	22,753	19,504
Total current assets	944,723	1,197,500
Property, plant and equipment, net	9,538,788	9,475,571
Other assets
Regulatory assets	816,532	809,011
Derivative instruments	13,954	15,357
Other	41,665	36,066
Total other assets	872,151	860,434
Total assets	11,355,662	11,533,505
Current liabilities
Current portion of long-term debt	855,791	605,633
Accounts payable	264,482	362,580
Accounts payable to affiliates	23,103	48,371
Regulatory liabilities	64,043	68,809
Taxes accrued	156,996	116,376
Accrued interest	54,720	53,749
Dividend payable to parent	0	66,926
Derivative instruments	17,897	85,518
Other	72,462	75,671
Total current liabilities	1,509,494	1,483,633
Deferred credits and other liabilities
Deferred income taxes	1,825,660	1,775,448
Deferred investment tax credits	44,074	44,725
Regulatory liabilities	445,098	444,442
Asset retirement obligations	42,797	42,207
Derivative instruments	36,185	38,325
Customer advances	224,627	226,097
Pension and employee benefit obligations	183,004	222,707
Other	70,806	69,561
Total deferred credits and other liabilities	2,872,251	2,863,512
Commitments and contingencies
Capitalization
Long-term debt	2,629,346	2,880,642
Common stock - 100 shares authorized at $0.01 par value; 100 shares outstanding at March 31, 2012 and Dec. 31, 2011	0	0
Additional paid-in capital	3,316,386	3,316,386
Retained earnings	1,027,917	1,001,709
Accumulated other comprehensive income (loss)	268	(12,377)
Total common stockholder's equity	4,344,571	4,305,718
Total liabilities and equity	$ 11,355,662	$ 11,533,505