Pension & Postretirement Expenses (Schedule Of Net Periodic Pension And Net Postretirement Plan Expenses) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Pension And Postretirement Plan Expenses [Line Items]
Service cost	$ 18	$ 19	$ 36	$ 38
Interest cost	50	47	100	93
Expected return on plan assets	(88)	(88)	(176)	(175)
Net amortization	16	30	33	61
Total	$ (4)	$ 8	$ (7)	$ 17