CONSOLIDATED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 7,345	$ 3,585
Accounts receivable, net	270,112	300,882
Accounts receivable from affiliates	11,735	4,909
Accrued unbilled revenues	205,714	276,212
Inventories	217,274	205,562
Regulatory assets	83,278	92,072
Derivative instruments	7,357	1,945
Deferred incomes taxes	42,037	62,662
Prepaid taxes	30,633	81,162
Prepayments and other	20,093	22,698
Total current assets	895,578	1,051,689
Property, plant and equipment, net	12,628,372	12,172,211
Other assets
Regulatory assets	875,952	906,275
Derivative instruments	2,870	3,478
Other	22,790	18,224
Total other assets	901,612	927,977
Total assets	14,425,562	14,151,877
Current liabilities
Current portion of long-term debt	5,277	8,103
Short-term debt	0	14,000
Borrowings under utility money pool arrangement	51,000	0
Accounts payable	312,998	352,701
Accounts payable to affiliates	38,632	76,643
Regulatory liabilities	74,661	152,823
Taxes accrued	132,230	166,660
Accrued interest	29,716	49,698
Dividends payable to parent	82,785	83,374
Derivative instruments	5,324	8,881
Other	72,029	78,910
Total current liabilities	804,652	991,793
Deferred credits and other liabilities
Deferred income taxes	2,907,922	2,720,860
Deferred investment tax credits	31,362	33,466
Regulatory liabilities	498,206	471,421
Asset retirement obligations	247,990	240,508
Derivative instruments	9,130	13,020
Customer advances	184,475	198,526
Pension and employee benefit obligations	188,695	200,774
Other	62,471	63,864
Total deferred credits and other liabilities	4,130,251	3,942,439
Commitments and contingencies
Capitalization
Long-term debt	4,211,396	4,097,493
Common stock — 100 shares authorized at $0.01 par value; 100 shares outstanding at Sept. 30, 2016 and Dec. 31, 2015, respectively	0	0
Additional paid in capital	3,655,741	3,620,824
Retained earnings	1,646,782	1,523,164
Accumulated other comprehensive loss	(23,260)	(23,836)
Total common stockholders’ equity	5,279,263	5,120,152
Total liabilities and equity	$ 14,425,562	$ 14,151,877