Other Retirement Plans Other Retirement Plans (Schedule of Costs of Multiemployer Plans) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Multiemployer Plans [Line Items]
Multiemployer plan, period contributions	$ 29.1	$ 20.7	$ 22.6
Multiemployer Plans, Pension [Member]
Multiemployer Plans [Line Items]
Multiemployer plan, period contributions	27.9	19.4	21.7
Multiemployer Plans, Postretirement Benefit [Member]
Multiemployer Plans [Line Items]
Multiemployer plan, period contributions	$ 1.2	$ 1.3	$ 0.9
Workforce Subject to Collective Bargaining Arrangements [Member] | Maximum [Member]
Multiemployer Plans [Line Items]
Entity number of employees during period	2,509	1,538	1,111
Workforce Subject to Collective Bargaining Arrangements [Member] | Minimum [Member]
Multiemployer Plans [Line Items]
Entity number of employees during period	308	308	254