Leases (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Leases [Abstract]
Capital leases, plant and equipment	$ 23.1	$ 21.6
Capital leases, accumulated depreciation	7.2	6.1
Operating leases, rent expense	87.0	82.7	$ 65.8
Capital leases, present value future lease payments	10.1
Lessor, total lease payments collected	171.6	182.7	183.6
Lessor, payments reducing lease receivable	94.6	97.4	$ 92.2
Property, Plant and Equipment [Line Items]
Plant and equipment, at cost	22,333.7	21,490.2
Accumulated depreciation	11,996.1	$ 11,566.5
Assets Leased to Others
Property, Plant and Equipment [Line Items]
Plant and equipment, at cost	2,900.0
Accumulated depreciation	$ 500.0