Discontinued Operations (Components of income from discontinued operations, net of tax) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Discontinued Operations and Disposal Groups [Abstract]
Operating revenue	$ 31.9	$ 27.5	$ 92.9	$ 80.4
Operating expenses	(34.1)	(22.4)	(95.9)	(68.8)
Income (loss) from discontinued operations before income taxes	(2.2)	5.1	(3.0)	11.6
Income tax (provision)/benefit	0.8	(1.9)	1.1	(4.3)
Income (loss) from discontinued operations, net of tax	$ (1.4)	$ 3.2	$ (1.9)	$ 7.3