Retirement Plans and Post Retirement Benefits Level 3 Rollforward (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2016
Assets Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) [Roll Forward]
Fair value of plan assets, beginning of year balance		$ 237.4		$ 268.0
Fair value of plan assets, end of year balance		237.4		268.0	$ 239.9
Multi-strategy Funds
Assets Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) [Roll Forward]
Fair value of plan assets, beginning of year balance	[1]	84.2
Fair value of plan assets, end of year balance	[1]	84.2			75.1
Significant Unobservable Inputs (Level 3)
Assets Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) [Roll Forward]
Fair value of plan assets, beginning of year balance		13.3
Fair value of plan assets, end of year balance		13.3			12.2
Significant Unobservable Inputs (Level 3) | Multi-strategy Funds
Assets Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) [Roll Forward]
Fair value of plan assets, beginning of year balance		13.3	[1]	26.1
Total unrealized gains (losses)		0.3
Defined Benefit Plan, Redemptions		(1.5)		(13.0)
Defined Benefit Plan, Mangement Fees		0.1		0.2
Fair value of plan assets, end of year balance		$ 13.3	[1]	$ 26.1	$ 12.2	[1]

[1] The multi-strategy funds invest in various hedge funds that employ a fund of funds strategy.