CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Current assets
Cash and cash equivalents	$ 3,763	$ 32,912
Accounts receivable, net	317,039	305,469
Accounts receivable from affiliates	12,063	21,042
Investments in utility money pool arrangement	52,000	0
Accrued unbilled revenues	304,544	297,535
Inventories	253,997	223,058
Regulatory assets	196,311	176,596
Deferred income taxes	33,349	13,877
Derivative instruments	4,930	6,294
Prepayments and other	19,504	54,235
Total current assets	1,197,500	1,131,018
Property, plant and equipment, net	9,475,571	9,200,556
Other assets
Regulatory assets	809,011	824,205
Derivative instruments	15,357	18,035
Other	36,066	55,016
Total other assets	860,434	897,256
Total assets	11,533,505	11,228,830
Current liabilities
Current portion of long-term debt	605,633	6,970
Short-term debt	0	269,400
Accounts payable	362,580	382,380
Accounts payable to affiliates	48,371	28,270
Regulatory liabilities	68,809	50,018
Taxes accrued	116,376	94,321
Accrued interest	53,749	48,866
Dividend payable to parent	66,926	66,828
Derivative instruments	85,518	29,047
Other	75,671	100,984
Total current liabilities	1,483,633	1,077,084
Deferred credits and other liabilities
Deferred income taxes	1,775,448	1,539,583
Deferred investment tax credits	44,725	47,338
Regulatory liabilities	444,442	472,846
Asset retirement obligations	42,207	72,687
Derivative instruments	38,325	43,220
Customer advances	226,097	244,345
Pension and employee benefit obligations	222,707	303,946
Other	69,561	61,334
Total deferred credits and other liabilities	2,863,512	2,785,299
Commitments and contingencies
Capitalization
Long-term debt	2,880,642	3,228,253
Common stock - authorized 100 shares of $0 01 par value; outstanding 100 shares	0	0
Additional paid in capital	3,316,386	3,255,586
Retained earnings	1,001,709	875,151
Accumulated other comprehensive (loss) income	(12,377)	7,457
Total common stockholder's equity	4,305,718	4,138,194
Total liabilities and equity	$ 11,533,505	$ 11,228,830