STATEMENTS OF INCOME (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
OPERATING REVENUES	$ 2,453.1	$ 2,262.2	$ 2,141.2
COST OF SALES	1,106.6	965.9	879.1
OPERATING EXPENSES
Other operation and maintenance	453.2	438.8	446.3
Depreciation and amortization	270.8	248.4	248.7
Taxes other than income	84.5	83.8	77.7
Total operating expenses	808.5	771.0	772.7
OPERATING INCOME	538.0	525.3	489.4
OTHER INCOME (EXPENSE)
Allowance for borrowed funds used during construction	4.2	6.6	6.2
Other income	4.8	8.1	8.2
Other expense	(1.9)	(4.6)	(4.3)
Net other income	7.1	10.1	10.1
INTEREST EXPENSE
Interest on long-term debt	139.7	130.6	124.2
Allowance for borrowed funds used during construction	(2.4)	(3.4)	(3.5)
Interest on short-term debt and other interest charges	4.2	2.1	3.9
Interest expense	141.5	129.3	124.6
INCOME BEFORE TAXES	403.6	406.1	374.9
INCOME TAX EXPENSE	111.6	113.5	94.6
NET INCOME	$ 292.0	$ 292.6	$ 280.3