Derivatives - Notional Amounts of Foreign Currency Forward Contracts (Details) - Foreign currency contracts - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Designated as hedges | Euro
Notional amounts of foreign currency forward contracts
Notional amounts	$ 253.0	$ 391.9
Designated as hedges | Canadian dollar
Notional amounts of foreign currency forward contracts
Notional amounts	64.5	99.0
Designated as hedges | British pound
Notional amounts of foreign currency forward contracts
Notional amounts	35.8	57.2
Designated as hedges | Australian dollar
Notional amounts of foreign currency forward contracts
Notional amounts		36.1
Designated as hedges | Swiss franc
Notional amounts of foreign currency forward contracts
Notional amounts		28.9
Designated as hedges | Other
Notional amounts of foreign currency forward contracts
Notional amounts	74.4	50.9
Not designated as hedges | Euro
Notional amounts of foreign currency forward contracts
Notional amounts	349.0	289.0
Not designated as hedges | Canadian dollar
Notional amounts of foreign currency forward contracts
Notional amounts	42.8	110.3
Not designated as hedges | British pound
Notional amounts of foreign currency forward contracts
Notional amounts	89.6	78.1
Not designated as hedges | Indian rupee
Notional amounts of foreign currency forward contracts
Notional amounts	71.6	61.0
Not designated as hedges | Mexican peso
Notional amounts of foreign currency forward contracts
Notional amounts	49.9	52.3
Not designated as hedges | Japanese yen
Notional amounts of foreign currency forward contracts
Notional amounts	31.4	37.7
Not designated as hedges | Australian dollar
Notional amounts of foreign currency forward contracts
Notional amounts	40.9	35.2
Not designated as hedges | Russian ruble
Notional amounts of foreign currency forward contracts
Notional amounts	25.3
Not designated as hedges | Brazilian real
Notional amounts of foreign currency forward contracts
Notional amounts		32.5
Not designated as hedges | Other
Notional amounts of foreign currency forward contracts
Notional amounts	157.3	145.6
Maximum individual currency exposure within various other currencies	$ 25.0	$ 25.0