Retirement Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Defined Benefit Pension Plans
Defined Benefit Plans, Net Periodic Benefit Cost [Abstract]
Service cost	$ 1.8	$ 1.7	$ 3.4	$ 3.5
Interest cost	3.0	2.7	6.0	5.4
Expected return on assets	(3.0)	(2.8)	(5.9)	(5.6)
Other	0.3	1.1	0.6	2.2
Total benefit cost	2.1	2.7	4.1	5.5
Contributions to pension plans	1.1		2.2
Estimated employer contribution to pension plans during current fiscal year			5.0
Retiree Health Care Plan
Defined Benefit Plans, Net Periodic Benefit Cost [Abstract]
Interest cost	0.2	0.1	0.4	0.3
Net gain	0.0	(0.1)	0.0	(0.3)
Prior service credit	(0.2)	0.0	(0.4)	0.0
Total benefit cost	0.0	$ 0.0	0.0	$ 0.0
Contributions to retiree health care plan	$ 0.2		$ 0.5