CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 5,315	$ 3,585
Accounts receivable, net	260,221	300,882
Accounts receivable from affiliates	6,548	4,909
Investments in utility money pool arrangement	93,000	0
Accrued unbilled revenues	195,838	276,212
Inventories	165,397	205,562
Regulatory assets	83,512	92,072
Deferred income taxes	58,713	62,662
Derivative instruments	2,216	1,945
Prepaid taxes	4,867	81,162
Prepayments and other	22,347	22,698
Total current assets	897,974	1,051,689
Property, plant and equipment, net	12,269,953	12,172,211
Other assets
Regulatory assets	900,878	906,275
Derivative instruments	3,092	3,478
Other	17,946	18,224
Total other assets	921,916	927,977
Total assets	14,089,843	14,151,877
Current liabilities
Current portion of long-term debt	7,255	8,103
Short-term Debt	0	14,000
Accounts payable	287,755	352,701
Accounts payable to affiliates	38,030	76,643
Regulatory liabilities	111,143	152,823
Taxes accrued	211,137	166,660
Accrued interest	27,409	49,698
Dividends payable to parent	83,914	83,374
Derivative instruments	5,749	8,881
Other	72,513	78,910
Total current liabilities	844,905	991,793
Deferred Tax Liabilities, Net, Noncurrent	2,781,159	2,720,860
Deferred credits and other liabilities
Deferred investment tax credits	32,765	33,466
Regulatory liabilities	488,181	471,421
Asset retirement obligations	242,933	240,508
Derivative instruments	11,729	13,020
Customer advances	190,428	198,526
Pension and employee benefit obligations	184,510	200,774
Other	64,079	63,864
Total deferred credits and other liabilities	$ 3,995,784	$ 3,942,439
Commitments and contingencies
Capitalization
Long-term debt	$ 4,097,000	$ 4,097,493
Common stock — 100 shares authorized at $0.01 par value; 100 shares outstanding at March 31, 2016 and Dec. 31, 2015, respectively	0	0
Additional paid in capital	3,620,824	3,620,824
Retained earnings	1,555,123	1,523,164
Accumulated other comprehensive loss	(23,793)	(23,836)
Total common stockholder’s equity	5,152,154	5,120,152
Total liabilities and equity	$ 14,089,843	$ 14,151,877