Other Retirement Plans (Schedule of Costs of Multiemployer Plans) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Multiemployer Plans [Line Items]
Multiemployer plan, period contributions	$ 8.0	$ 3.6
Multiemployer Plans, Pension [Member]
Multiemployer Plans [Line Items]
Multiemployer plan, period contributions	7.6	3.4
Multiemployer Plans, Postretirement Benefit [Member]
Multiemployer Plans [Line Items]
Multiemployer plan, period contributions	$ 0.4	$ 0.2
Workforce Subject to Collective Bargaining Arrangements [Member] | Minimum [Member]
Multiemployer Plans [Line Items]
Entity number of employees during period	778	308
Workforce Subject to Collective Bargaining Arrangements [Member] | Maximum [Member]
Multiemployer Plans [Line Items]
Entity number of employees during period	1,149	1,608