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		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Pension And Postretirement Plan Expenses [Line Items]
Service cost	$ 23	$ 27	$ 47	$ 53
Interest cost	60	57	122	113
Expected return on plan assets	(86)	(83)	(172)	(166)
Net amortization	37	58	73	116
Total	$ 34	$ 59	$ 70	$ 116