Employee Benefits Schedule of Changes in Benefit Obligations and Fair Value of Plan Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Special termination benefits			$ 0
Benefit payments	(2.9)		(2.1)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	71.7		55.2
Company contributions to the plan	8.1		8.1
Benefit payments	(2.9)		(2.1)
Fair value of plan assets, end of period	81.4		71.7		55.2
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net actuarial loss recognized in AOCI	(13.6)	[1]	13.5	[1]	(10.0)	[1]
Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of period	118.0		129.7
Service cost	2.6		3.3		4.0
Interest cost	5.3		4.8		5.1
Special termination benefits	1.9		0		0
Loss on curtailment in current period	(8.2)		0		(2.2)
Settlements	(2.3)		0
Benefit payments	(5.5)		(5.5)
Actuarial loss (gain)	20.8		(14.3)
Benefit obligation, end of period	132.6		118.0		129.7
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	71.7		55.3
Actual gain on plan assets	4.5		10.4
Company contributions to the plan	13.0		11.5
Benefit payments	(5.5)		(5.5)
Settlements	(2.3)		0
Fair value of plan assets, end of period	81.4		71.7		55.3
Underfunded status (current and long-term)	(51.2)		(46.3)
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Amounts included in accounts payable and accrued expenses	(4.3)		(5.5)
Amounts included in other long-term liabilities	(46.9)		(40.8)
Total amount recognized in balance sheets	(51.2)		(46.3)
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net actuarial loss recognized in AOCI	21.2		9.5
Prior service cost recognized in AOCI	16.1		30.1
Total amount recognized in AOCI	37.3		39.6
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of period	5.9		6.7
Service cost	0		0.1		0.1
Interest cost	0.3		0.3		0.3
Special termination benefits	0		0		0
Loss on curtailment in current period	(0.2)		0		0
Settlements	0		0
Benefit payments	0		(0.1)
Actuarial loss (gain)	0.6		(1.1)
Benefit obligation, end of period	6.6		5.9		6.7
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0		0
Actual gain on plan assets	0		0
Company contributions to the plan	0		0.1
Benefit payments	0		(0.1)
Settlements	0		0
Fair value of plan assets, end of period	0		0		0
Underfunded status (current and long-term)	(6.6)		(5.9)
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Amounts included in accounts payable and accrued expenses	(0.3)		(0.2)
Amounts included in other long-term liabilities	(6.3)		(5.7)
Total amount recognized in balance sheets	(6.6)		(5.9)
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net actuarial loss recognized in AOCI	0.6		0.2
Prior service cost recognized in AOCI	1.4		3.0
Total amount recognized in AOCI	$ 2.0		$ 3.2

[1] Presented net of income tax benefit of $8.5 million for the year ended December 31, 2014, net of income tax expense of $8.3 million during the year ended December 31, 2013 and net of income tax benefit of $6.3 million during the year ended December 31, 2012