Debt - Revolving Loan Arrangements (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Revolving loans
Total Amount Committed by Lenders	$ 748.7
Outstanding Borrowings	61.0
Outstanding Letters of Credit	129.7
Total Amount Available	558.0
Revolving Loans
Revolving loans
Outstanding Letters of Credit	129.7	$ 137.7
Other lines of credit
Revolving loans
Total Amount Committed by Lenders	248.7
Outstanding Letters of Credit	128.9
Total Amount Available	$ 119.8
2015 Credit Agreement | US Dollar revolving loan
Revolving loans
Weighted Average Interest Rate (as a percent)	1.60%
Total Amount Committed by Lenders	$ 500.0
Outstanding Borrowings	61.0
Outstanding Letters of Credit	0.8
Total Amount Available	$ 438.2