Segment Data - Revenues to Unaffiliated Customers and Long-lived Assets Including Property, Plant and Equipment (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 20,248	$ 17,117	$ 17,290
Long-Lived Assets	45,029	45,043	45,101
Corporate
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-Lived Assets	465	411	377
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	10,969	9,716	9,730
Long-Lived Assets	36,037	36,468	37,053
EMEA (a)
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	4,751	3,928	3,837
Long-Lived Assets	6,004	5,890	5,519
Greater Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	3,272	2,568	2,726
Long-Lived Assets	1,662	1,521	1,328
Other (a)
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	1,255	905	997
Long-Lived Assets	$ 860	753	824
Middle East and Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues		448	478
Long-Lived Assets		$ 55	$ 37