Financial Instruments, Risk Management and Fair Value Measurements - Recurring Fair Value Measurements (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019
Assets
Derivatives	$ 73.7		$ 8.3
Liabilities
Derivative Liabilities	32.5		17.2
Foreign exchange contracts
Assets
Derivatives	73.7		8.3
Liabilities
Derivative Liabilities	27.2		16.3
Interest rate contracts
Liabilities
Derivative Liabilities	5.3		$ 0.9
Fair Value, Measurements, Recurring
Assets
Other	17.9	$ 20.2
Total assets	83.4	20.4
Liabilities
Other	27.1	32.8
Total liabilities	51.4	41.9
Fair Value, Measurements, Recurring | Foreign exchange contracts
Assets
Derivatives	65.5	0.2
Liabilities
Derivative Liabilities	19.0	8.2
Fair Value, Measurements, Recurring | Interest rate contracts
Liabilities
Derivative Liabilities	5.3	0.9
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Other	17.9	20.2
Total assets	17.9	20.2
Liabilities
Other	26.0	29.7
Total liabilities	26.0	29.7
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Foreign exchange contracts
Assets
Derivatives	0.0	0.0
Liabilities
Derivative Liabilities	0.0	0.0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Interest rate contracts
Liabilities
Derivative Liabilities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Assets
Other	0.0	0.0
Total assets	65.5	0.2
Liabilities
Other	1.1	3.1
Total liabilities	25.4	12.2
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign exchange contracts
Assets
Derivatives	65.5	0.2
Liabilities
Derivative Liabilities	19.0	8.2
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Interest rate contracts
Liabilities
Derivative Liabilities	5.3	0.9
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Assets
Other	0.0	0.0
Total assets	0.0	0.0
Liabilities
Other	0.0	0.0
Total liabilities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Foreign exchange contracts
Assets
Derivatives	0.0	0.0
Liabilities
Derivative Liabilities	0.0	0.0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Interest rate contracts
Liabilities
Derivative Liabilities	$ 0.0	$ 0.0