CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Operating revenues
Electric	$ 682,279	$ 704,153
Natural gas	383,004	428,191
Steam and other	10,769	12,103
Total operating revenues	1,076,052	1,144,447
Operating expenses
Electric fuel and purchased power	310,899	323,797
Cost of natural gas sold and transported	256,877	304,938
Cost of sales - steam and other	4,167	5,121
Operating and maintenance expenses	168,382	170,671
Demand side management program expenses	29,444	30,322
Depreciation and amortization	83,589	79,969
Taxes (other than income taxes)	33,788	34,321
Total operating expenses	887,146	949,139
Operating income	188,906	195,308
Other income, net	1,032	1,663
Allowance for funds used during construction - equity	2,726	1,619
Interest charges and financing costs
Interest charges - includes other financing costs of $1,790 and $1,516, respectively	48,291	45,399
Allowance for funds used during construction - debt	(1,161)	(726)
Total interest charges and financing costs	47,130	44,673
Income before income taxes	145,534	153,917
Income taxes	52,249	57,287
Net income	$ 93,285	$ 96,630