CONDENSED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Operating revenues	$ 367.8	$ 337.5	$ 801.2	$ 741.7
Cost of fuel, natural gas, and purchased power	164.3	154.2	376.9	342.4
Operating and maintenance expense	116.9	106.0	224.2	213.3
Depreciation and amortization expense	27.8	24.0	51.2	47.9
Taxes other than income taxes	11.9	11.5	24.6	24.3
Operating income	46.9	41.8	124.3	113.8
Miscellaneous income	5.9	4.5	10.9	7.6
Interest expense	(10.3)	(10.6)	(21.2)	(21.4)
Other expense	(4.4)	(6.1)	(10.3)	(13.8)
Income before taxes	42.5	35.7	114.0	100.0
Provision for income taxes	15.8	12.3	41.9	33.7
Net income	26.7	23.4	72.1	66.3
Preferred stock dividend requirements	(0.8)	(0.8)	(1.6)	(1.6)
Net income attributed to common shareholder	$ 25.9	$ 22.6	$ 70.5	$ 64.7