Pension & Postretirement Expenses (Summary Of Net Periodic Pension And Net Postretirement Plan Expenses) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Pension And Postretirement Plan Expenses [Line Items]
Service cost	$ 18	$ 19
Interest cost	50	46
Expected return on plan assets	(88)	(87)
Net amortization	17	31
Total	$ (3)	$ 9