Commitments and Contingencies - Schedule of Loss Contingencies by Contingency (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023
Loss Contingencies [Line Items]
Reserve for environmental liabilities, current	$ 31	$ 31
Reserve for environmental liabilities, noncurrent	201	211
Total reserves for environmental liabilities	232	242
Total asbestos-related liabilities	417	422
Total asbestos-related assets	321	301
Net asbestos-related liabilities	96	121
Restricted
Insurance receivables for asbestos-related liabilities	50	50
Total self-insured liabilities	328	333
Insurance receivables, current	6	6
Insurance receivables, noncurrent	14	14
Total insurance receivables	20	20
Asbestos Issue
Loss Contingencies [Line Items]
Total asbestos-related assets	271	251
Restricted
Cash	19	20
Investments	252	231
Other current liabilities
Loss Contingencies [Line Items]
Total asbestos-related liabilities	58	58
Restricted
Total self-insured liabilities	87	86
Other noncurrent liabilities
Loss Contingencies [Line Items]
Total asbestos-related liabilities	359	364
Restricted
Total self-insured liabilities	219	226
Other current assets
Loss Contingencies [Line Items]
Total asbestos-related assets	27	28
Other noncurrent assets
Loss Contingencies [Line Items]
Total asbestos-related assets	294	273
Accrued compensation and benefits
Restricted
Total self-insured liabilities	$ 22	$ 21