Retirement Benefits (Change in Projected Benefit Obligation) (Details) - Defined Benefit Pension Plan - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Service cost	$ 39.8	$ 44.7	$ 46.7
Interest cost	102.8	94.1	116.0
U.S.
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Obligation at beginning of year	3,335.3	3,423.8
Service cost	18.3	21.3	23.4
Interest cost	73.9	68.9	91.2
Amendments	1.5	0.5
Actuarial (gain) loss	(793.8)	(17.7)
Settlements	(19.2)	(3.0)
Participant contributions	0.0	0.0
Benefits paid	(165.2)	(158.5)
Currency translation and other	0.0	0.0
Obligation at end of year	2,450.8	3,335.3	3,423.8
International
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Obligation at beginning of year	1,969.6	1,949.7
Service cost	21.5	23.4	23.3
Interest cost	28.9	25.2	24.8
Amendments	0.1	0.0
Actuarial (gain) loss	(575.2)	(30.9)
Settlements	(0.9)	(1.8)
Participant contributions	1.2	1.3
Benefits paid	(53.0)	(52.8)
Currency translation and other	(254.7)	55.5
Obligation at end of year	$ 1,137.5	$ 1,969.6	$ 1,949.7