Retirement Benefits (Schedule of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]				Other non-operating income (expense), net	Other non-operating income (expense), net
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5.7		$ 9.9	$ 17.5	$ 30.3
Interest Cost	47.7		25.5	142.0	77.5
Expected return on plan assets	(44.3)		(58.6)	(131.9)	(178.1)
Prior service cost amortization	0.3		0.3	1.0	0.9
Actuarial loss amortization	18.0		20.2	53.8	61.2
Settlements	0.3		3.1	1.4	5.1
Curtailments				(1.9)	0.0
Other	0.2		0.2	0.7	1.2
Net Periodic Cost (Benefit)	27.9		0.6	82.6	(1.9)
U.S. | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.7		4.6	8.2	13.8
Interest Cost	32.5		18.4	97.5	55.2
Expected return on plan assets	(31.7)		(42.0)	(95.3)	(126.2)
Prior service cost amortization	0.3		0.3	0.9	0.9
Actuarial loss amortization	14.9		16.6	44.7	49.9
Settlements	0.0		3.1	0.9	4.9
Curtailments				0.0	0.0
Other	0.0		0.0	0.0	0.0
Net Periodic Cost (Benefit)	18.7		1.0	56.9	(1.5)
International | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	3.0		5.3	9.3	16.5
Interest Cost	15.2		7.1	44.5	22.3
Expected return on plan assets	(12.6)		(16.6)	(36.6)	(51.9)
Prior service cost amortization	0.0		0.0	0.1	0.0
Actuarial loss amortization	3.1		3.6	9.1	11.3
Settlements	0.3		0.0	0.5	0.2
Curtailments		$ (1.9)		(1.9)	0.0
Other	0.2		0.2	0.7	1.2
Net Periodic Cost (Benefit)	$ 9.2		$ (0.4)	$ 25.7	$ (0.4)