Income Taxes - Provision for Income Taxes from Continuing Operations (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Federal	$ 102	$ (50)	$ 235
State and local, including Puerto Rico	46	47	41
Foreign	290	400	300
Total, Current	438	397	576
Domestic	(286)	(184)	(577)
Foreign	(2)	(101)	(56)
Total, Deferred	(288)	(286)	(633)
Income tax provision	150	111	(57)
Unrecognized tax benefits interest and penalties reflected in current year	$ 5	$ 1	$ 26