Stock-based Compensation (Details 7) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 23.3	[1]	$ 29.3	[1]	$ 15.2	[1]
Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 4.8		$ 5.4		$ 4.5
Weighted-average fair value of grants, per share	$ 19.55		$ 18.76		$ 14.34

[1] Stock-Based compensation expense was recorded in our Corporate and other business segment.