Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues
Electric	$ 1,963.6	$ 2,017.7	$ 2,020.5
Gas	432.2	401.5	398.5
Total revenues	2,395.8	2,419.2	2,419.0
Expenses
Fuel	561.4	638.6	692.3
Purchased power	104.1	78.9	71.4
Cost of natural gas sold	158.5	135.5	137.0
Other	537.9	528.9	518.4
Depreciation and amortization	328.3	313.5	302.6
Taxes, other than income	193.1	192.0	189.8
Total expenses	1,883.3	1,887.4	1,911.5
Income from operations	512.5	531.8	507.5
Other income
Allowance for other funds used during construction	24.1	17.2	10.5
Other income, net	7.1	2.4	4.8
Total other income	31.2	19.6	15.3
Interest charges
Interest expense	117.3	117.9	111.7
Allowance for borrowed funds used during construction	(11.5)	(8.3)	(5.1)
Total interest charges	105.8	109.6	106.6
Income before provision for income taxes	437.9	441.8	416.2
Provision for income taxes	152.2	165.5	155.9
Net income	285.7	276.3	260.3
Other comprehensive income, net of tax
Gain on cash flow hedges	0.8	3.5	0.7
Total other comprehensive income, net of tax	0.8	3.5	0.7
Comprehensive income	$ 286.5	$ 279.8	$ 261.0