Pension And Postretirement Plan Expenses (Summary Of Net Periodic Pension And Net Postretirement Plan Expenses) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Pension [Member]
Pension And Postretirement Plan Expenses [Line Items]
Service cost	$ 21	$ 21
Interest cost	56	55
Expected return on plan assets	(80)	(82)
Net amortization	46	42
Total	43	36
Postretirement [Member]
Pension And Postretirement Plan Expenses [Line Items]
Service cost	1	1
Interest cost	4	4
Net amortization	(3)	(2)
Total	$ 2	$ 3