Retirement Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Expense Assumptions:
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, General and Administrative Expense	Selling, General and Administrative Expense	Selling, General and Administrative Expense
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, General and Administrative Expense	Selling, General and Administrative Expense	Selling, General and Administrative Expense
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, General and Administrative Expense	Selling, General and Administrative Expense	Selling, General and Administrative Expense
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Amortization of Prior Service Cost (Credit), Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, General and Administrative Expense	Selling, General and Administrative Expense	Selling, General and Administrative Expense
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Curtailment Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, General and Administrative Expense	Selling, General and Administrative Expense	Selling, General and Administrative Expense
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Settlement Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Selling, General and Administrative Expense	Selling, General and Administrative Expense	Selling, General and Administrative Expense
Pension Plan | United States
Components of Net Periodic Benefit Cost (Credit):
Service cost	$ 0	$ 0	$ 0
Interest cost	78	56	47
Expected return on plan assets	(131)	(150)	(171)
Net actuarial (gain) loss	28	16	(214)
Settlement (gain) loss	1	1	0
Amortization of prior service cost (credit)	0	0	0
Other	$ 0	$ 0	$ 0
Expense Assumptions:
Discount rate	5.08%	2.52%	2.25%
Expected return on plan assets	8.25%	7.00%	6.90%
Pension Plan | Foreign Plan
Components of Net Periodic Benefit Cost (Credit):
Service cost	$ 16	$ 20	$ 27
Interest cost	68	39	32
Expected return on plan assets	(77)	(81)	(112)
Net actuarial (gain) loss	86	(116)	(115)
Settlement (gain) loss	6	5	(1)
Amortization of prior service cost (credit)	0	0	1
Other	$ 0	$ 0	$ (1)
Expense Assumptions:
Discount rate	4.36%	1.79%	1.35%
Expected return on plan assets	5.02%	3.70%	4.90%
Rate of compensation increase	3.00%	2.85%	2.75%
Interest crediting rate	1.69%	1.44%	1.50%
Postretirement Benefits
Components of Net Periodic Benefit Cost (Credit):
Service cost	$ 0	$ 1	$ 1
Interest cost	4	2	2
Expected return on plan assets	(9)	(9)	(8)
Net actuarial (gain) loss	(5)	4	(35)
Settlement (gain) loss	0	0	0
Amortization of prior service cost (credit)	(4)	(4)	(4)
Other	$ 0	$ 0	$ 0
Expense Assumptions:
Discount rate	4.92%	2.30%	1.90%
Expected return on plan assets	6.64%	5.29%	5.30%
Continuing Operations | Pension Plan | United States
Components of Net Periodic Benefit Cost (Credit):
Net periodic benefit cost (credit) included in continuing operations	$ (24)	$ (77)	$ (338)
Continuing Operations | Pension Plan | Foreign Plan
Components of Net Periodic Benefit Cost (Credit):
Net periodic benefit cost (credit) included in continuing operations	99	(133)	(169)
Continuing Operations | Postretirement Benefits
Components of Net Periodic Benefit Cost (Credit):
Net periodic benefit cost (credit) included in continuing operations	$ (14)	$ (6)	$ (44)