Supplemental Financial Information - Other Income (Expense), Net (Detail) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Royalty Income, Nonoperating				$ 64	$ 51	$ 0
Insurance Recoveries				35	0	0
Income (Loss) from Equity Method Investments				18	8	3
Foreign Currency Transaction Gain (Loss), Realized				(23)	(14)	(11)
Losses on debt extinguishment	$ (57)	$ (3)	$ (13)	(59)	(16)	(73)
Gains on previously held investments				0	0	24
Other Nonoperating Income				4	0	3
Other Nonoperating Income (Expense)				43	305	(101)
Other Nonoperating Income (Expense)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)				(2)	(13)	(44)
Vyaire Medical
Income (Loss) from Equity Method Investments				$ 6	$ 288	$ (3)