Income Taxes (Schedule Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Period over which the amount of unrecognized tax benefits are not expected to significantly increase or decrease	12 months
Unrecognized tax benefits, beginning	$ 158	$ 132
Additions for current year tax positions	15	13
Additions for prior year tax positions	18	8
Reductions for prior year tax positions	(22)	(8)
Acquisitions and divestitures	4	21
Reductions for settlements with tax authorities	(5)	(3)
Reductions for expiration of statutes of limitations	(9)	(5)
Unrecognized tax benefits, ending	$ 159	$ 158