Benefit Plans (Net Periodic Benefit Costs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net Periodic Benefit Costs [Abstract]
Interest cost	$ 4.4	$ 5.0	$ 5.1
Net loss (gain)	3.4	16.0	11.5
Unrecognized past service cost recognized in the year	(1.2)	0	0.1
The effect of any curtailment or settlement	0	2.2	0
Net periodic benefit cost	$ 6.6	$ 23.2	$ 16.7