Retirement and Postretirement Benefit Plans (Schedule of Allocation of Plan Assets) (Details) - Pension Plan [Member]	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation	100.00%	100.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation	32.00%	35.00%
Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual Allocation	68.00%	65.00%
Minimum [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	0.31	0.31
Minimum [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	0.63	0.63
Maximum [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	0.37	0.37
Maximum [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	0.69	0.69