Other Retirement Plans (Schedule of Multi-Employer Plan Covered Employees and Contributions) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Multi-Employer Plan Covered Employees and Contributions [Line Items]
Multi-employer plans, contributions	$ 8.8	$ 8.3	$ 17.1	$ 17.3
Multi-Employer Plans, Pension [Member]
Multi-Employer Plan Covered Employees and Contributions [Line Items]
Multi-employer plans, contributions	8.0	7.2	15.8	15.3
Multi-Employer Plans, Postretirement Benefit [Member]
Multi-Employer Plan Covered Employees and Contributions [Line Items]
Multi-employer plans, contributions	$ 0.8	$ 1.1	$ 1.3	$ 2.0
Workforce Subject to Collective Bargaining Arrangements [Member] | Minimum [Member]
Multi-Employer Plan Covered Employees and Contributions [Line Items]
Multi-employer plans, covered employees	1,308	1,149	1,098	778
Workforce Subject to Collective Bargaining Arrangements [Member] | Maximum [Member]
Multi-Employer Plan Covered Employees and Contributions [Line Items]
Multi-employer plans, covered employees	2,167	2,392	2,167	2,392