Significant Accounting Policies - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2015
Leases [Abstract]
Operating lease term	12 months
Restricted Cash and Investments [Abstract]
Restricted Investments, Current	$ 73,000,000	$ 77,000,000
Revenue from Contract with Customer [Abstract]
Maximum cash collection period from customer	60 days
Expense Recognition [Abstract]
Advertising costs	$ 1,000,000	2,000,000	$ 2,000,000
Research and development expense	$ 55,000,000	$ 51,000,000	$ 55,000,000
Earnings Per Share [Abstract]
Antidilutive securities excluded from calculation of earnings per share	1.2	1.2	1.2
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Net decrease to retained earnings	$ (2,868,000,000)	$ (3,097,000,000)
Shares of warrants with a strike price	$ 128.66
Allowance for credit losses on accounts receivable incurred	$ 0	0	$ 0
Asbestos Trust [Member]
Restricted Cash and Investments [Abstract]
Increase (Decrease) in Restricted Cash				$ 335,000,000
Restricted Investments, Current	36,000,000	37,000,000
Available-for-sale securities, fair value	248,000,000	243,000,000
Environmental Trust [Member]
Restricted Cash and Investments [Abstract]
Restricted Investments, Current	37,000,000	40,000,000
Available-for-sale securities, fair value	120,000,000	$ 124,000,000
Selling, General and Administrative Expenses [Member]
Foreign Currency Translation [Abstract]
Devaluation charge	$ 5,000,000
Argentina [Member]
Foreign Currency Translation [Abstract]
Percentage of Peso devaluation against Dollar	50.00%
Minimum | Affiliates [Member]
Principles of consolidation and basis of presentation [Abstract]
Percentage of ownership under equity method	20.00%
Minimum | Trademarks and Trade Names [Member]
Goodwill and other intangibles [Abstract]
Useful life (in years)	3 years
Minimum | Intellectual Property [Member]
Goodwill and other intangibles [Abstract]
Useful life (in years)	3 years
Minimum | Customer and Supplier Relationships [Member]
Goodwill and other intangibles [Abstract]
Useful life (in years)	10 years
Minimum | Buildings [Member]
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, Useful Life	12 years
Minimum | Machinery and Equipment [Member]
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, Useful Life	2 years
Maximum | Affiliates [Member]
Principles of consolidation and basis of presentation [Abstract]
Percentage of ownership under equity method	50.00%
Maximum | Trademarks and Trade Names [Member]
Goodwill and other intangibles [Abstract]
Useful life (in years)	20 years
Maximum | Intellectual Property [Member]
Goodwill and other intangibles [Abstract]
Useful life (in years)	20 years
Maximum | Customer and Supplier Relationships [Member]
Goodwill and other intangibles [Abstract]
Useful life (in years)	24 years
Maximum | Buildings [Member]
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, Useful Life	35 years
Maximum | Machinery and Equipment [Member]
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, Useful Life	25 years