Employee Benefit Plans - Level 3 Reconciliation (Details) - Defined Benefit Pension Plans - Level 3 $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets, beginning balance	$ 0.0
From ND acquisition	104.7
Actual return on assets:
Assets held at end of period	(4.0)
Assets sold during the period	(0.2)
Sales	(1.7)
Foreign currency exchange rate changes	(3.0)
Fair value of plan assets, ending balance	95.8
Illiquid credit
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets, beginning balance	0.0
From ND acquisition	56.5
Actual return on assets:
Assets held at end of period	0.3
Assets sold during the period	0.0
Sales	0.0
Foreign currency exchange rate changes	(1.6)
Fair value of plan assets, ending balance	55.2
Hedge Funds
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets, beginning balance	0.0
From ND acquisition	46.3
Actual return on assets:
Assets held at end of period	(4.3)
Assets sold during the period	0.0
Sales	0.0
Foreign currency exchange rate changes	(1.4)
Fair value of plan assets, ending balance	40.6
Real Estate
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets, beginning balance	0.0
From ND acquisition	1.9
Actual return on assets:
Assets held at end of period	0.0
Assets sold during the period	(0.2)
Sales	(1.7)
Foreign currency exchange rate changes	0.0
Fair value of plan assets, ending balance	$ 0.0