Equity (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-Based Compensation
Share based compensation recognized	$ 5.3	$ 3.5	$ 15.6	$ 13.9
Unrecognized stock-based compensation expense	36.6		36.6
Estimated amortized share based compensation expense, remainder of 2014	5.4		5.4
Estimated amortized share based compensation expense, 2015	15.9		15.9
Estimated amortized share based compensation expense, 2016	8.0		8.0
Estimated amortized share based compensation expense, 2017	1.2		1.2
Unrecognized compensation expense not expected to vest	$ 6.1		$ 6.1
Restricted stock units
Share-Based Compensation
Units granted during period (in shares)			0.3
Units vested in period (in shares)			0.2
Outstanding at the end of the period (in shares)	0.7		0.7
Performance stock units
Share-Based Compensation
Units granted during period (in shares)			0.2
Stock options
Share-Based Compensation
Stock options outstanding at the end of the period (in shares)	0.7		0.7
Options not yet exercisable, outstanding at the end of the period (in shares)	0.2		0.2