Pension & Postretirement Expenses (Summary Of Net Periodic Pension And Net Postretirement Plan Expenses) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Pension And Postretirement Plan Expenses [Line Items]
Service cost	$ 21	$ 22
Interest cost	42	50
Expected return on plan assets	(86)	(88)
Net amortization	53	40
Total	$ 30	$ 24