Retirement Benefits (Benefit Liability Exceeds Value of Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Pension Plans with PBO in Excess of Plan Assets:
Defined Benefit Plan, Funding Status [Extensible Enumeration]	Defined Benefit Plan, Unfunded Plan [Member]
Pension Plans with ABO in Excess of Plan Assets:
Defined Benefit Plan, Funding Status [Extensible Enumeration]	Defined Benefit Plan, Unfunded Plan [Member]
Defined Benefit Pension Plan
Pension Plans with PBO in Excess of Plan Assets:
PBO	$ 59.9
Pension Plans with ABO in Excess of Plan Assets:
ABO	55.4
Defined Benefit Pension Plan | U.S.
Pension Plans with PBO in Excess of Plan Assets:
PBO	2,446.5	$ 2,194.5
Fair value of plan assets	2,321.1	2,108.5
PBO in excess of plan assets	125.4	86.0
Pension Plans with ABO in Excess of Plan Assets:
ABO	2,394.5	47.1
Fair value of plan assets	2,321.1	0.0
ABO in excess of plan assets	73.4	47.1
Defined Benefit Pension Plan | International
Pension Plans with PBO in Excess of Plan Assets:
PBO	326.1	295.1
Fair value of plan assets	207.2	182.9
PBO in excess of plan assets	118.9	112.2
Pension Plans with ABO in Excess of Plan Assets:
ABO	139.8	144.3
Fair value of plan assets	42.0	56.3
ABO in excess of plan assets	$ 97.8	$ 88.0