CONSOLIDATED BALANCE SHEETS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current assets
Cash and cash equivalents	$ 18,120	$ 21,089
Accounts receivable, net	316,348	328,675
Accounts receivable from affiliates	31,053	19,136
Investments in utility money pool arrangement	250,000	72,000
Accrued unbilled revenues	207,157	270,917
Inventories	181,711	238,007
Regulatory assets	167,115	150,163
Deferred income taxes	67,319	87,267
Derivative instruments	2,343	6,576
Prepayments and other	25,234	32,629
Total current assets	1,266,400	1,226,459
Property, plant and equipment, net	10,901,885	10,742,397
Other assets
Regulatory assets	838,996	826,037
Derivative instruments	6,471	6,905
Other	50,163	52,520
Total other assets	895,630	885,462
Total assets	13,063,915	12,854,318
Current liabilities
Current portion of long-term debt	282,389	282,143
Accounts payable	386,917	451,243
Accounts payable to affiliates	32,727	45,902
Regulatory liabilities	92,617	79,499
Taxes accrued	205,841	154,194
Accrued interest	31,980	48,492
Dividends payable to parent	64,022	65,134
Derivative instruments	5,857	6,734
Other	91,988	89,571
Total current liabilities	1,194,338	1,222,912
Deferred credits and other liabilities
Deferred income taxes	2,235,374	2,206,179
Deferred investment tax credits	38,496	39,230
Regulatory liabilities	449,883	424,690
Asset retirement obligations	61,129	60,398
Derivative instruments	22,068	23,366
Customer advances	248,292	251,062
Pension and employee benefit obligations	131,513	167,127
Other	68,853	66,855
Total deferred credits and other liabilities	3,255,608	3,238,907
Commitments and contingencies
Capitalization
Long-term debt	3,887,712	3,590,500
Common stock — 100 shares authorized at $0.01 par value; 100 shares outstanding at March 31, 2014 and Dec. 31, 2013	0	0
Additional paid in capital	3,441,290	3,441,290
Retained earnings	1,308,428	1,384,047
Accumulated other comprehensive loss	(23,461)	(23,338)
Total common stockholder’s equity	4,726,257	4,801,999
Total liabilities and equity	$ 13,063,915	$ 12,854,318