Retirement Benefits (Schedule of Allocation of Plan Assets, Actual and Target Allocations) (Details) - Defined Benefit Pension Plan [Member]	Sep. 30, 2021	Sep. 30, 2020
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	100.00%	100.00%
United States [Member] | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	30.70%	64.40%
United States [Member] | Equity Securities | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	2.50%	41.70%
United States [Member] | Equity Securities | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	51.20%	81.70%
United States [Member] | Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	67.70%	35.00%
United States [Member] | Debt Securities | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	58.80%	28.30%
United States [Member] | Debt Securities | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	87.50%	48.30%
United States [Member] | Other Investment Asset
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	1.60%	0.60%
Target Allocation Ranges	0.00%	0.00%
United States [Member] | Other Investment Asset | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	0.00%	0.00%
United States [Member] | Other Investment Asset | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	0.00%	0.00%
United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	100.00%	100.00%
United Kingdom | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	42.30%	39.60%
United Kingdom | Equity Securities | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	50.00%	50.00%
United Kingdom | Equity Securities | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	90.00%	90.00%
United Kingdom | Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	57.30%	60.10%
United Kingdom | Debt Securities | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	45.00%	45.00%
United Kingdom | Debt Securities | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	70.00%	70.00%
United Kingdom | Other Investment Asset
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	0.40%	0.30%
Target Allocation Ranges	0.00%	0.00%
United Kingdom | Other Investment Asset | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	0.00%	0.00%
United Kingdom | Other Investment Asset | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	0.00%	0.00%
Japan
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	100.00%	100.00%
Japan | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	40.30%	39.70%
Japan | Equity Securities | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	36.00%	36.00%
Japan | Equity Securities | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	44.00%	44.00%
Japan | Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	58.80%	59.40%
Japan | Debt Securities | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	55.00%	55.00%
Japan | Debt Securities | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	63.00%	63.00%
Japan | Other Investment Asset
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	0.90%	0.90%
Japan | Other Investment Asset | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	0.00%	0.00%
Japan | Other Investment Asset | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	2.00%	2.00%