CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Operating revenues
Electric	$ 897,516	$ 884,305	$ 2,337,547	$ 2,385,297
Natural gas	152,763	151,553	659,738	716,731
Steam and other	8,898	8,846	29,585	30,647
Total operating revenues	1,059,177	1,044,704	3,026,870	3,132,675
Operating expenses
Electric fuel and purchased power	318,624	311,347	890,509	930,107
Cost of natural gas sold and transported	42,379	44,953	270,182	354,825
Cost of sales — steam and other	3,664	3,596	10,874	12,938
Operating and maintenance expenses	191,011	186,379	570,343	560,021
Demand side management program expenses	31,015	33,040	88,094	96,622
Depreciation and amortization	111,803	104,228	330,593	305,517
Taxes (other than income taxes)	45,076	45,987	146,851	146,895
Total operating expenses	743,572	729,530	2,307,446	2,406,925
Operating income	315,605	315,174	719,424	725,750
Other income, net	544	1,222	1,837	2,674
Allowance for funds used during construction — equity	5,343	3,958	13,714	10,155
Interest charges and financing costs
Interest charges — includes other financing costs of $1,271, $1,611, $4,735 and $4,671, respectively	46,664	44,875	138,982	131,859
Allowance for funds used during construction — debt	(1,995)	(1,467)	(5,222)	(3,890)
Total interest charges and financing costs	44,669	43,408	133,760	127,969
Income before income taxes	276,823	276,946	601,215	610,610
Income taxes	103,216	103,865	224,390	228,063
Net income	$ 173,607	$ 173,081	$ 376,825	$ 382,547