Pension Benefits (Details) employees in Thousands, $ in Millions		12 Months Ended
	Sep. 04, 2013 USD ($)	Dec. 31, 2015 USD ($) employees	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Actuarial Gain Recognized in Other Comprehensive Income, Before Tax		$ 3.0	$ (106.4)	$ 61.6
Defined Contribution Plan, Cost Recognized		$ 7.8	7.3	7.3
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Pension Plan, Number of Participants and Beneficiaries		9,300
Defined Benefit Pension Plans Active Employees | employees		2
Percentage of Compensation, Defined Benefit Plan Employee Contribution		3.00%
Defined Benefit Plan, Funded Status of Plan		$ (90.3)	(91.0)
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer	$ 55.0
Pension Expense Recognized		25.6	8.3	29.7
Actuarial Gain Recognized in Other Comprehensive Income, Before Tax		1.9	(102.0)	53.8
Supplemental Employee Retirement Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Funded Status of Plan		30.4	31.0
Pension Expense Recognized		2.1	1.8	1.8
Actuarial Gain Recognized in Other Comprehensive Income, Before Tax		$ 1.5	$ (7.0)	$ 1.5