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		9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Pension [Member]
Pension And Postretirement Plan Expenses [Line Items]
Service cost	$ 21	$ 21	$ 62	$ 62
Interest cost	56	55	167	166
Expected return on plan assets	(80)	(82)	(239)	(246)
Net amortization	46	42	138	127
Total	43	36	128	109
Postretirement [Member]
Pension And Postretirement Plan Expenses [Line Items]
Service cost	1	1	2	3
Interest cost	4	4	12	13
Net amortization	(3)	(2)	(9)	(6)
Total	$ 2	$ 3	$ 5	$ 10