Employee Benefit Plans - Funded Status of Plan (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
U.S. Qualified Plans
Funded Status:
Fair value of plan assets	$ 1,619.9	$ 0.0
Projected benefit obligation	1,665.8	0.0
Funded status at December 31, 2015	(45.9)
Funded Status Recognized in Balance Sheet:
Long-term assets	17.3
Current liabilities	0.0
Long-term liabilities	(63.2)
Total liability at December 31, 2015	(45.9)
Plans with projected and accumulated benefit obligation in excess of plan assets:
Projected and accumulated benefit obligation	1,645.7
Fair value of plan assets	$ 1,582.5
Weighted-average assumptions as of December 31:
Discount rate	4.65%
U.S Non-Qualified Plans
Funded Status:
Fair value of plan assets	$ 0.0	0.0
Projected benefit obligation	73.0	0.0
Funded status at December 31, 2015	(73.0)
Funded Status Recognized in Balance Sheet:
Long-term assets	0.0
Current liabilities	(5.2)
Long-term liabilities	(67.8)
Total liability at December 31, 2015	(73.0)
Plans with projected and accumulated benefit obligation in excess of plan assets:
Projected and accumulated benefit obligation	73.0
Fair value of plan assets	$ 0.0
Weighted-average assumptions as of December 31:
Discount rate	4.65%
UK Plans
Funded Status:
Fair value of plan assets	$ 1,203.8	0.0
Projected benefit obligation	1,287.7	$ 0.0
Funded status at December 31, 2015	(83.9)
Funded Status Recognized in Balance Sheet:
Long-term assets	0.0
Current liabilities	0.0
Long-term liabilities	(83.9)
Total liability at December 31, 2015	(83.9)
Plans with projected and accumulated benefit obligation in excess of plan assets:
Projected and accumulated benefit obligation	1,287.7
Fair value of plan assets	$ 1,203.8
Weighted-average assumptions as of December 31:
Discount rate	3.75%