CONDENSED CONSOLIDATED STATEMENTS OF INCOME (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
Operating revenues	$ 433.4	$ 404.2
Cost of fuel, natural gas, and purchased power	212.6	188.2
Operating and maintenance expense	107.3	107.3
Depreciation and amortization expense	23.4	23.9
Taxes other than income taxes	12.7	12.8
Operating income	77.4	72.0
Miscellaneous income	5.0	3.1
Interest expense	(10.9)	(10.8)
Other expense	(5.9)	(7.7)
Income before taxes	71.5	64.3
Provision for income taxes	26.1	21.4
Net income	45.4	42.9
Preferred stock dividend requirements	(0.8)	(0.8)
Net income attributed to common shareholder	$ 44.6	$ 42.1