Pension & Postretirement Expenses (Summary Of Net Periodic Pension And Net Postretirement Plan Expenses) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2016
Pension And Postretirement Plan Expenses [Line Items]
Service cost	$ 22	$ 27	$ 67	$ 81
Interest cost	50	60	149	181
Expected return on plan assets	(88)	(92)	(264)	(276)
Net amortization	40	43	121	128
Total	$ 24	$ 38	$ 73	$ 114
Change in Assumptions for Pension Plans [Member] | Scenario, Forecast [Member]
Pension And Postretirement Plan Expenses [Line Items]
Discount rate used to measure service cost for pension expense					4.60%
Discount rate used to measure interest cost for pension expense					3.50%
Defined benefit plan, assumptions used calculating net periodic benefit cost, discount rate					4.35%
Change in estimated service cost and interest cost for pension expense					$ (38)
Change in estimated service cost and interest cost for pension expense per share					$ (0.04)