Retirement Plan And Other Post-Retirement Benefits (Narrative) (Details) $ in Millions	6 Months Ended
	Mar. 31, 2018 USD ($)
Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Company's contributions	$ 27.6
VEBA Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Company's contributions	2.1
Minimum [Member] | VEBA Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated future contributions in remainder of fiscal year	0.5
Maximum [Member] | Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated future contributions in remainder of fiscal year	5.0
Maximum [Member] | VEBA Trusts [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated future contributions in remainder of fiscal year	$ 1.0