Retirement Plans and Post Retirement Benefits Level 3 Rollforward (Details) (USD $) In Millions, unless otherwise specified												12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Multi-strategy Funds [Member]		Dec. 31, 2011 Multi-strategy Funds [Member]		Dec. 31, 2012 Real Estate [Member]		Dec. 31, 2011 Real Estate [Member]		Dec. 31, 2012 Significant Unobservable Inputs (Level 3) [Member]	Dec. 31, 2011 Significant Unobservable Inputs (Level 3) [Member]	Dec. 31, 2012 Significant Unobservable Inputs (Level 3) [Member] Multi-strategy Funds [Member]		Dec. 31, 2011 Significant Unobservable Inputs (Level 3) [Member] Multi-strategy Funds [Member]		Dec. 31, 2012 Significant Unobservable Inputs (Level 3) [Member] Real Estate [Member]		Dec. 31, 2011 Significant Unobservable Inputs (Level 3) [Member] Real Estate [Member]
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	$ 259.3	$ 247.1	$ 255.2	$ 49.5	[1]	$ 46.4	[1]	$ 15.2	[2]	$ 14.5	[2]	$ 60.9	$ 59.3	$ 46.4	[1]	$ 45.4		$ 14.5	[2]	$ 13.9
Total unrealized gains (losses)												4.1	2.0	3.1		0.8		1.0		1.2
Net income												(0.3)	(0.6)					(0.3)		(0.6)
Mangement fees													0.2			0.2
Fair value of plan assets, end of year balance	$ 259.3	$ 247.1	$ 255.2	$ 49.5	[1]	$ 46.4	[1]	$ 15.2	[2]	$ 14.5	[2]	$ 64.7	$ 60.9	$ 49.5	[1]	$ 46.4	[1]	$ 15.2	[2]	$ 14.5	[2]

[1] The multi-strategy funds invest in various hedge funds of fund strategies.

[2] Real estate investments are primarily invested in U.S. commercial real estate.