Income Statement (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
OPERATING REVENUES
Gas utility	$ 819.1	$ 954.1	$ 1,066.0
Electric utility	635.9	608.0	528.6
Nonutility	870.2	567.4	494.3
Total operating revenues	2,325.2	2,129.5	2,088.9
OPERATING EXPENSES
Cost of gas sold	375.4	504.7	618.1
Cost of fuel and purchased power	240.4	235.0	194.3
Cost of nonutility revenues	385.3	243.3	207.5
Other operating	652.2	538.4	514.0
Depreciation and amortization	244.3	229.1	211.9
Taxes other than income taxes	57.6	62.2	63.0
Total operating expenses	1,955.2	1,812.7	1,808.8
OPERATING INCOME	370.0	316.8	280.1
OTHER INCOME (EXPENSE)
Equity in earnings (losses) of unconsolidated affiliates	(32.0)	(8.6)	3.4
Other income (expense) - net	(3.5)	4.8	13.7
Total other income (expense)	(35.5)	(3.8)	17.1
Interest expense	106.5	104.6	100.0
INCOME BEFORE INCOME TAXES	228.0	208.4	197.2
Income taxes	86.4	74.7	64.1
Net income	$ 141.6	$ 133.7	$ 133.1
AVERAGE COMMON SHARES OUTSTANDING (in shares)	81.8	81.2	80.7
DILUTED COMMON SHARES OUTSTANDING (in shares)	81.8	81.3	81.0
EARNINGS PER SHARE OF COMMON STOCK:
BASIC (in dollars per share)	$ 1.73	$ 1.65	$ 1.65
DILUTED (in dollars per share)	$ 1.73	$ 1.64	$ 1.64