Consolidated Condensed Statements of Capital (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Balance, Dec. 31, 2015		$ 2,559.0
Net income	$ 69.4	148.5
Other comprehensive loss, after tax	(6.2)	(5.4)
Common stock issued		(1.6)
Impact of Merger		0.0
Dividends and dividend equivalents		(135.4)
Stock compensation expense		6.4
Restricted stock—dividends		(1.6)
Cumulative effect of change in accounting		2.6
Equity contribution		22.1
Other		(0.4)
Balance, Sept. 30, 2016	2,594.2	2,594.2
Common Stock [Member]
Balance, Dec. 31, 2015		$ 235.3
Balance, Dec. 31, 2015, shares		235.3
Common stock issued		$ 0.2
Common stock issued, shares		0.2
Impact of Merger		$ (235.5)
Impact of Merger, shares		(235.3)
Balance, Sept. 30, 2016	$ 0.0	$ 0.0
Balance, Sept. 30, 2016, shares	0.0	0.0
Additional Paid-in Capital [Member]
Balance, Dec. 31, 2015		$ 1,894.5
Common stock issued		(1.8)
Impact of Merger		235.5
Stock compensation expense		6.4
Restricted stock—dividends		(1.6)
Equity contribution		22.1
Other		(0.4)
Balance, Sept. 30, 2016	$ 2,154.7	2,154.7
Retained Earnings [Member]
Balance, Dec. 31, 2015		441.4
Net income		148.5
Dividends and dividend equivalents		(135.4)
Cumulative effect of change in accounting		2.6
Balance, Sept. 30, 2016	457.1	457.1
Accumulated Other Comprehensive Income (Loss) [Member]
Balance, Dec. 31, 2015		(12.2)
Other comprehensive loss, after tax		(5.4)
Balance, Sept. 30, 2016	$ (17.6)	$ (17.6)