Intangible Assets - Components of Intangible Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Sep. 30, 2021
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 20,295	$ 20,122
Accumulated Amortization	(7,730)	(7,385)
Finite-Lived Intangible Assets, Net	12,565	12,737
Unamortized intangible assets	46	46
Trademarks
Finite And Indefinite Lived Intangible Assets [Line Items]
Unamortized intangible assets	2	2
Acquired in-process research and development
Finite And Indefinite Lived Intangible Assets [Line Items]
Unamortized intangible assets	44	44
Developed technology
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	14,539	14,399
Accumulated Amortization	(5,237)	(4,983)
Finite-Lived Intangible Assets, Net	9,302	9,417
Customer relationships
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,687	4,658
Accumulated Amortization	(1,922)	(1,839)
Finite-Lived Intangible Assets, Net	2,765	2,818
Product rights
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	118	123
Accumulated Amortization	(82)	(83)
Finite-Lived Intangible Assets, Net	36	40
Trademarks
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	409	409
Accumulated Amortization	(142)	(137)
Finite-Lived Intangible Assets, Net	267	271
Patents and other
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Carrying Amount	542	533
Accumulated Amortization	(347)	(342)
Finite-Lived Intangible Assets, Net	$ 195	$ 191