Retirement Benefits (Schedule of Allocation of Plan Assets, Actual and Target Allocations) (Details) - Defined Benefit Pension Plan [Member]	Sep. 30, 2019	Sep. 30, 2018
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	100.00%	100.00%
United States [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	60.60%	65.10%
United States [Member] | Equity Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	41.40%	41.50%
United States [Member] | Equity Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	81.40%	81.50%
United States [Member] | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	37.90%	33.10%
United States [Member] | Debt Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	28.60%	28.50%
United States [Member] | Debt Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	48.60%	48.50%
United States [Member] | Other Investment Asset [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	1.50%	1.80%
United States [Member] | Other Investment Asset [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	0.00%	0.00%
United States [Member] | Other Investment Asset [Member] | 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 [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	41.60%	44.80%
United Kingdom | Equity Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	30.00%	30.00%
United Kingdom | Equity Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	60.00%	60.00%
United Kingdom | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	57.80%	54.80%
United Kingdom | Debt Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	45.00%	45.00%
United Kingdom | Debt Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	70.00%	70.00%
United Kingdom | Other Investment Asset [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	0.60%	0.40%
United Kingdom | Other Investment Asset [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	0.00%	0.00%
United Kingdom | Other Investment Asset [Member] | 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 [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	41.40%	41.00%
Japan | Equity Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	36.00%	36.00%
Japan | Equity Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	44.00%	44.00%
Japan | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	57.70%	58.10%
Japan | Debt Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	55.00%	55.00%
Japan | Debt Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	63.00%	63.00%
Japan | Other Investment Asset [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	0.90%	0.90%
Japan | Other Investment Asset [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	0.00%	0.00%
Japan | Other Investment Asset [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Ranges	2.00%	2.00%