Consolidated Condensed Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net Income	$ 80.9	$ 133.0	$ 276.7	$ 340.6
Cash flow hedges
Realized gains, net of tax	11.4	0.0	11.4	0.0
Reclassification of net losses (gains) to net income	(0.1)	0.0	(0.1)	0.0
Total other comprehensive income	11.3	0.0	11.3	0.0
Comprehensive income attributed to common shareholders	$ 92.2	$ 133.0	$ 288.0	$ 340.6