Employee Benefit Plans (Details 5) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Recognized in Other Comprehensive Income:
Net actuarial loss (gain)	$ 2.1	$ 13.7
Amortization of net actuarial loss (gain)	(1.1)	(0.1)
Amortization of prior service cost (credit)	(0.1)	(0.1)
Total change in other comprehensive income	$ 0.9	$ 13.5