CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Operating revenues
Electric	$ 881,102	$ 898,811	$ 2,376,935	$ 2,368,041
Natural gas	159,808	137,349	839,332	730,569
Steam and other	8,201	8,140	30,091	29,576
Total operating revenues	1,049,111	1,044,300	3,246,358	3,128,186
Operating expenses
Electric fuel and purchased power	368,860	355,727	1,052,400	998,395
Cost of natural gas sold and transported	60,073	43,881	487,159	403,198
Cost of sales — steam and other	3,538	3,398	11,951	12,211
Operating and maintenance expenses	185,510	192,073	549,935	553,266
Demand side management program expenses	36,120	38,016	105,993	104,075
Depreciation and amortization	95,075	88,577	283,506	267,206
Taxes (other than income taxes)	38,862	32,887	122,467	104,120
Total operating expenses	788,038	754,559	2,613,411	2,442,471
Operating income	261,073	289,741	632,947	685,715
Other income, net	1,720	946	3,429	3,845
Allowance for funds used during construction — equity	12,315	8,815	36,697	21,529
Interest charges and financing costs
Interest charges — includes other financing costs of $1,546, $1,747, $4,798, and $5,118, respectively	42,540	43,187	128,941	127,806
Allowance for funds used during construction — debt	(4,564)	(3,187)	(13,584)	(8,438)
Total interest charges and financing costs	37,976	40,000	115,357	119,368
Income before income taxes	237,132	259,502	557,716	591,721
Income taxes	82,973	93,236	195,362	211,551
Net income	$ 154,159	$ 166,266	$ 362,354	$ 380,170