Income Taxes (Schedule Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
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	$ 195	$ 159
Additions for current year tax positions	27	25
Additions for prior year tax positions	17	29
Reductions for prior year tax positions	(6)	(8)
Acquisitions and divestitures	1	0
Reductions for settlements with tax authorities	(5)	0
Reductions for expiration of statutes of limitations	(10)	(10)
Unrecognized tax benefits, ending	$ 219	$ 195