Debt Credit Facility Term Loan (Details) - USD ($) $ in Millions		1 Months Ended
	Nov. 29, 2019	Sep. 30, 2019	Feb. 29, 2020	Nov. 30, 2019
2019 Credit Agreement
Line of Credit Facility [Line Items]
Short-term Debt		$ 250.0	$ 250.0	$ 250.0
Debt Instrument, Interest Rate During Period		0.75%
Debt, Weighted Average Interest Rate			2.41%
2019 revolving credit facility
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity	$ 1,250.0
Credit facility additional borrowing capacity	$ 750.0
Letters of credit outstanding under 2018 revolving facility			$ 1.3
Credit facility, amount outstanding			$ 323.0	$ 237.0
Credit facility, interest rate at period end			2.89%
2019 revolving credit facility | Minimum
Line of Credit Facility [Line Items]
Credit facility, unused capacity, commitment fee percentage	0.10%
2019 revolving credit facility | Minimum | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Credit facility, interest rate	1.00%
2019 revolving credit facility | Maximum
Line of Credit Facility [Line Items]
Credit facility, unused capacity, commitment fee percentage	0.25%
2019 revolving credit facility | Maximum | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Credit facility, interest rate	1.625%