Debt - Revolving Loan Arrangements (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Revolving lines of credit
Total Amount Committed by Lenders	$ 737.6
Outstanding Borrowings	124.0
Outstanding Letters of Credit	130.9
Total Amount Available	482.7
Revolving Loans
Revolving lines of credit
Outstanding Letters of Credit	130.9	$ 137.7
Other lines of credit
Revolving lines of credit
Total Amount Committed by Lenders	237.6
Outstanding Letters of Credit	129.8
Total Amount Available	$ 107.8
2015 Credit Agreement | US Dollar revolving loan
Revolving lines of credit
Weighted Average Interest Rate (as a percent)	1.80%
Total Amount Committed by Lenders	$ 500.0
Outstanding Borrowings	124.0
Outstanding Letters of Credit	1.1
Total Amount Available	$ 374.9