Intangible Assets - Components of Intangible Assets (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 20,287	$ 20,122
Accumulated Amortization	(8,067)	(7,385)
Net Carrying Amount	12,220	12,737
Unamortized intangible assets	46	46
Acquired in-process research and development
Finite And Indefinite Lived Intangible Assets [Line Items]
Unamortized intangible assets	44	44
Trademarks
Finite And Indefinite Lived Intangible Assets [Line Items]
Unamortized intangible assets	2	2
Developed technology
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	14,535	14,399
Accumulated Amortization	(5,491)	(4,983)
Net Carrying Amount	9,044	9,417
Customer relationships
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,686	4,658
Accumulated Amortization	(2,005)	(1,839)
Net Carrying Amount	2,681	2,818
Product rights
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	115	123
Accumulated Amortization	(82)	(83)
Net Carrying Amount	33	40
Trademarks
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	408	409
Accumulated Amortization	(146)	(137)
Net Carrying Amount	262	271
Patents and other
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	543	533
Accumulated Amortization	(343)	(342)
Net Carrying Amount	$ 200	$ 191