Consolidated Condensed Income Statements (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating Revenues	$ 1,004.6	$ 946.6
Operating Expenses
Fuel and purchased power	272.3	255.1
Cost of gas sold	112.8	100.2
Other operation and maintenance	350.3	329.6
Depreciation and amortization	68.4	61.2
Property and revenue taxes	27.7	28.2
Total Operating Expenses	831.5	774.3
Operating Income	173.1	172.3
Equity in earnings of transmission affiliate	14.7	13.7
Other Income, net	4.1	15.9
Interest Expense, net	31.9	25.2
Income Before Income Taxes	160.0	176.7
Income Tax Expense	55.3	60.8
Net Income	104.7	115.9
Preferred Stock Dividend Requirement	0.3	0.3
Earnings Available for Common Stockholder	$ 104.4	$ 115.6