Consolidated Condensed Income Statements (Unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Operating Revenues	$ 944.7	$ 991.7	$ 2,135.9	$ 2,320.4
Operating Expenses
Fuel and purchased power	258.7	286.0	512.5	553.6
Cost of gas sold	75.0	121.8	312.5	464.2
Other operation and maintenance	267.9	298.9	554.2	612.4
Depreciation and amortization	90.3	82.3	177.9	163.6
Property and revenue taxes	30.2	28.3	60.5	56.6
Total Operating Expenses	722.1	817.3	1,617.6	1,850.4
Operating Income	222.6	174.4	518.3	470.0
Income (Loss) from Equity Method Investments	16.1	15.1	31.7	30.5
Other Income, net	8.6	14.4	24.6	26.9
Interest Expense, net	61.5	57.4	120.4	120.8
Income from Continuing Operations Before Income Taxes	185.9	146.6	454.3	406.8
Income Tax Expense	66.6	48.6	162.9	137.9
Income from Continuing Operations	119.3	98.0	291.4	268.9
Income (Loss) from Discontinued Operations, Net of Tax	0	11.5	0	11.5
Net Income	119.3	109.5	291.4	280.4
Earnings Per Share (Basic)
Continuing operations	$ 0.52	$ 0.42	$ 1.26	$ 1.15
Discontinued operations	$ 0.00	$ 0.05	$ 0.00	$ 0.05
Total Earnings Per Share (Basic)	$ 0.52	$ 0.47	$ 1.26	$ 1.20
Earnings Per Share (Diluted)
Continuing operations	$ 0.51	$ 0.41	$ 1.25	$ 1.14
Discontinued operations	$ 0.00	$ 0.05	$ 0.00	$ 0.05
Total Earnings Per Share (Diluted)	$ 0.51	$ 0.46	$ 1.25	$ 1.19
Weighted Average Common Shares Outstanding (Millions)
Basic	230.4	233.7	230.5	233.7
Diluted	233.1	236.6	233.1	236.6
Dividends Per Share of Common Stock	$ 0.30	$ 0.26	$ 0.60	$ 0.52
Transmission Affiliate [Member]
Operating Expenses
Income (Loss) from Equity Method Investments	$ 16.2	$ 15.2	$ 31.8	$ 30.7