Retirement Benefits (Schedule of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 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	$ 5.8		$ 10.2	$ 11.8	$ 20.4
Interest Cost	47.4		26.0	94.3	52.0
Expected return on plan assets	(44.0)		(59.7)	(87.6)	(119.5)
Prior service cost amortization	0.4		0.3	0.7	0.6
Actuarial loss amortization	18.0		20.4	35.8	41.0
Settlements	1.1		1.1	1.1	2.0
Curtailments				(1.9)	0.0
Other	0.2		0.2	0.5	1.0
Net Periodic Cost (Benefit)	28.9		(1.5)	54.7	(2.5)
U.S. | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.8		4.6	5.5	9.2
Interest Cost	32.5		18.4	65.0	36.8
Expected return on plan assets	(31.8)		(42.1)	(63.6)	(84.2)
Prior service cost amortization	0.3		0.3	0.6	0.6
Actuarial loss amortization	15.0		16.6	29.8	33.3
Settlements	0.9		0.9	0.9	1.8
Curtailments				0.0	0.0
Other	0.0		0.0	0.0	0.0
Net Periodic Cost (Benefit)	19.7		(1.3)	38.2	(2.5)
International | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	3.0		5.6	6.3	11.2
Interest Cost	14.9		7.6	29.3	15.2
Expected return on plan assets	(12.2)		(17.6)	(24.0)	(35.3)
Prior service cost amortization	0.1		0.0	0.1	0.0
Actuarial loss amortization	3.0		3.8	6.0	7.7
Settlements	0.2		0.2	0.2	0.2
Curtailments		$ (1.9)		(1.9)	0.0
Other	0.2		0.2	0.5	1.0
Net Periodic Cost (Benefit)	$ 9.2		$ (0.2)	$ 16.5	$ 0.0