Financial Instruments (Cash Flow and Fair Value Hedges Location and Amounts Recognized) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Total Amounts Presented in the Consolidated Income Statement in which the Effects of Cash Flow and Fair Value Hedges are Recorded
Sales	$ 2,320.1	$ 2,065.2	$ 2,216.3	$ 2,254.7	$ 2,283.2	$ 2,224.0	$ 2,187.7	$ 2,224.0	$ 8,856.3	$ 8,918.9	$ 8,930.2
Cost of sales									5,858.1	5,975.5	6,189.5
Other income (expense), net									65.4	49.3	50.2
Interest expense									109.3	137.0	130.5
Other non-operating income (expense), net									30.7	66.7	5.1
(Gain) Loss Effects of Cash Flow Hedging:
Tax effects									(17.7)
Net (Gain) Loss Reclassified from OCI to Income									(57.7)
Tax effects										4.5	(9.2)
Net (Gain) Loss Reclassified from OCI to Income										12.3	$ (30.4)
Cash Flow Hedges | Sales
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									(0.2)
Tax effects									0.0
Net (Gain) Loss Reclassified from OCI to Income									(0.2)
Amount reclassified from OCI into income										0.5
Tax effects										0.1
Net (Gain) Loss Reclassified from OCI to Income										0.4
Cash Flow Hedges | Cost of Sales
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									(1.0)
Tax effects									(0.2)
Net (Gain) Loss Reclassified from OCI to Income									(0.8)
Amount reclassified from OCI into income										0.3
Tax effects										0.1
Net (Gain) Loss Reclassified from OCI to Income										0.2
Cash Flow Hedges | Other Income (Expense), Net
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									0.0
Tax effects									0.0
Net (Gain) Loss Reclassified from OCI to Income									0.0
Amount reclassified from OCI into income										(3.9)
Tax effects										(0.9)
Net (Gain) Loss Reclassified from OCI to Income										(3.0)
Cash Flow Hedges | Interest Expense
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									4.2
Tax effects									1.4
Net (Gain) Loss Reclassified from OCI to Income									2.8
Amount reclassified from OCI into income										19.9
Tax effects										5.2
Net (Gain) Loss Reclassified from OCI to Income										14.7
Cash Flow Hedges | Other Nonoperating Income (Expense), Net
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									(78.4)
Tax effects									(18.9)
Net (Gain) Loss Reclassified from OCI to Income									(59.5)
Amount reclassified from OCI into income										0.0
Tax effects										0.0
Net (Gain) Loss Reclassified from OCI to Income										0.0
Cash Flow Hedges | Forward Exchange Contracts | Sales
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									(0.2)
Amount reclassified from OCI into income										0.5
Cash Flow Hedges | Forward Exchange Contracts | Cost of Sales
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									(1.0)
Amount reclassified from OCI into income										0.3
Cash Flow Hedges | Forward Exchange Contracts | Other Income (Expense), Net
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									0.0
Amount reclassified from OCI into income										28.5
Cash Flow Hedges | Forward Exchange Contracts | Interest Expense
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									0.0
Amount reclassified from OCI into income										16.0
Cash Flow Hedges | Forward Exchange Contracts | Other Nonoperating Income (Expense), Net
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									(117.9)
Amount reclassified from OCI into income										0.0
Cash Flow Hedges | Forward Exchange Contracts, Excluded Component | Sales
(Gain) Loss Effects of Cash Flow Hedging:
Amount excluded from effectiveness testing recognized in earnings based on amortization approach									0.0
Cash Flow Hedges | Forward Exchange Contracts, Excluded Component | Cost of Sales
(Gain) Loss Effects of Cash Flow Hedging:
Amount excluded from effectiveness testing recognized in earnings based on amortization approach									0.0
Cash Flow Hedges | Forward Exchange Contracts, Excluded Component | Other Income (Expense), Net
(Gain) Loss Effects of Cash Flow Hedging:
Amount excluded from effectiveness testing recognized in earnings based on amortization approach									0.0
Cash Flow Hedges | Forward Exchange Contracts, Excluded Component | Interest Expense
(Gain) Loss Effects of Cash Flow Hedging:
Amount excluded from effectiveness testing recognized in earnings based on amortization approach									0.0
Cash Flow Hedges | Forward Exchange Contracts, Excluded Component | Other Nonoperating Income (Expense), Net
(Gain) Loss Effects of Cash Flow Hedging:
Amount excluded from effectiveness testing recognized in earnings based on amortization approach									17.0
Cash Flow Hedges | Other | Sales
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									0.0
Amount reclassified from OCI into income										0.0
Cash Flow Hedges | Other | Cost of Sales
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									0.0
Amount reclassified from OCI into income										0.0
Cash Flow Hedges | Other | Other Income (Expense), Net
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									0.0
Amount reclassified from OCI into income										(32.4)
Cash Flow Hedges | Other | Interest Expense
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									4.2
Amount reclassified from OCI into income										3.9
Cash Flow Hedges | Other | Other Nonoperating Income (Expense), Net
(Gain) Loss Effects of Cash Flow Hedging:
Amount reclassified from OCI into income									22.5
Amount reclassified from OCI into income										0.0
Fair Value Hedges | Sales
(Gain) Loss Effects of Fair Value Hedging
Total Gain (Loss) Recognized in Income									0.0	0.0
Fair Value Hedges | Cost of Sales
(Gain) Loss Effects of Fair Value Hedging
Total Gain (Loss) Recognized in Income									0.0	0.0
Fair Value Hedges | Other Income (Expense), Net
(Gain) Loss Effects of Fair Value Hedging
Total Gain (Loss) Recognized in Income									0.0	0.0
Fair Value Hedges | Interest Expense
(Gain) Loss Effects of Fair Value Hedging
Total Gain (Loss) Recognized in Income									0.0	0.0
Fair Value Hedges | Other Nonoperating Income (Expense), Net
(Gain) Loss Effects of Fair Value Hedging
Total Gain (Loss) Recognized in Income									0.0	0.0
Fair Value Hedges | Other | Sales
(Gain) Loss Effects of Fair Value Hedging
Hedges items									0.0	0.0
Derivatives designated as hedging instruments									0.0	0.0
Fair Value Hedges | Other | Cost of Sales
(Gain) Loss Effects of Fair Value Hedging
Hedges items									0.0	0.0
Derivatives designated as hedging instruments									0.0	0.0
Fair Value Hedges | Other | Other Income (Expense), Net
(Gain) Loss Effects of Fair Value Hedging
Hedges items									0.0	0.0
Derivatives designated as hedging instruments									0.0	0.0
Fair Value Hedges | Other | Interest Expense
(Gain) Loss Effects of Fair Value Hedging
Hedges items									0.5	4.3
Derivatives designated as hedging instruments									(0.5)	(4.3)
Fair Value Hedges | Other | Other Nonoperating Income (Expense), Net
(Gain) Loss Effects of Fair Value Hedging
Hedges items									0.0	0.0
Derivatives designated as hedging instruments									$ 0.0	$ 0.0