Supplemental Information (Payables and Accrued Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Sep. 30, 2016
Supplemental Information [Abstract]
Trade creditors	$ 659.5	$ 578.8
Customer advances	438.9	371.2
Accrued payroll and employee benefits	187.1	217.1
Pension and postretirement benefits	22.6	35.5
Dividends payable	207.5	186.9
Outstanding payments in excess of certain cash balances	4.5	11.9
Accrued interest expense	42.2	47.9
Derivative instruments	95.9	73.5
Severance and other costs associated with business restructuring and cost reduction actions	41.5	15.7
Other	114.6	113.7
Payables and accrued liabilities	$ 1,814.3	$ 1,652.2