Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues
Regulated electric	$ 2,014.9	$ 2,019.9	$ 1,949.6
Regulated gas	716.8	537.4	392.9
Unregulated	11.8	9.1	12.6
Total revenues	2,743.5	2,566.4	2,355.1
Expenses
Fuel	638.6	692.3	680.2
Purchased power	78.9	71.4	64.7
Cost of natural gas sold	271.6	209.7	142.2
Other	613.2	547.8	524.4
Operation and maintenance other expense	22.7	29.5	12.5
Depreciation and amortization	349.0	315.3	291.8
Taxes, other than income	207.4	195.0	184.7
Total expenses	2,181.4	2,061.0	1,900.5
Income from operations	562.1	505.4	454.6
Other income (expense)
Allowance for other funds used during construction	17.4	10.5	6.3
Other income	3.4	0.5	1.8
Total other income	20.8	11.0	8.1
Interest charges
Interest expense	195.1	176.4	165.0
Allowance for borrowed funds used during construction	(8.7)	(5.3)	(3.6)
Total interest charges	186.4	171.1	161.4
Income from continuing operations before provision for income taxes	396.5	345.3	301.3
Provision for income taxes	155.3	138.9	112.6
Net income from continuing operations	241.2	206.4	188.7
Discontinued operations
Income (loss) from discontinued operations	(106.3)	(125.4)	5.2
Provision (benefit) for income taxes	(38.6)	(49.4)	(3.8)
Income (loss) from discontinued operations, net	(67.7)	(76.0)	9.0
Net income	$ 173.5	$ 130.4	$ 197.7
Average common shares outstanding - Basic	233.1	223.1	215.0
Average common shares outstanding - Diluted	234.5	223.7	215.5
Earnings per share from continuing operations - Basic	$ 1.03	$ 0.92	$ 0.88
Earnings per share from continuing operations - Diluted	1.03	0.92	0.88
Earnings per share from discontinued operations - Basic	(0.29)	(0.34)	0.04
Earnings per share from discontinued operations - Diluted	(0.29)	(0.34)	0.04
Earnings per share - Basic	0.74	0.58	0.92
Earnings per share - Diluted	0.74	0.58	0.92
Dividends paid per common share outstanding	$ 0.90	$ 0.88	$ 0.88