Commitments and Contingencies - Narrative (Details) $ in Millions			1 Months Ended			3 Months Ended		6 Months Ended
	May 25, 2024 USD ($)	Apr. 12, 2024 USD ($)	Oct. 31, 2022 claim	Nov. 30, 2021 claim	Apr. 30, 2021 claim	Mar. 31, 2024 USD ($) claim state subsidiary	Mar. 31, 2023 USD ($)	Nov. 25, 2024 USD ($)	Mar. 31, 2024 USD ($) claim state defendant subsidiary	Mar. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Nov. 30, 2022 claim	Mar. 31, 2022 subsidiary
Loss Contingencies [Line Items]
Environmental loss contingencies payment period									20 years
Conditional asset retirement obligations | $						$ 10			$ 10		$ 13
Loss contingency, number of subsidiaries in civil enforcement action | subsidiary													2
Water provider AFFF settlement | $						$ 750	$ 0		$ 750	$ 0
FTC-Related Remediation and Litigation
Loss Contingencies [Line Items]
Loss contingency, pending claims, number												6
Aqueous Film Forming Foam ("AFFF") Litigation
Loss Contingencies [Line Items]
Loss contingency, number of subsidiaries named in lawsuits | subsidiary						2			2
AFFF Putative Class Actions
Loss Contingencies [Line Items]
Loss contingency, pending claims, number						46			46
Loss contingency, pending claims, number of states originated from | state						18			18
AFFF Individual or Mass Actions
Loss Contingencies [Line Items]
Loss contingency, pending claims, number						7,000			7,000
Loss contingency, pending claims, number of states originated from | state						52			52
AFFF Individual or Mass Actions | Colorado
Loss Contingencies [Line Items]
Loss contingency, number of defendants | defendant									7,000
AFFF Individual or Mass Actions | United States, Excluding Colorado
Loss Contingencies [Line Items]
Loss contingency, number of defendants | defendant									7,000
AFFF Municipal and Water Provider Cases
Loss Contingencies [Line Items]
Loss contingency, pending claims, number						815			815
Loss contingency, pending claims, number of states originated from | state						35			35
Water Provider AFFF Settlement Agreement
Loss Contingencies [Line Items]
Water provider AFFF settlement | $						$ 750
Water Provider AFFF Settlement Agreement | Subsequent Event
Loss Contingencies [Line Items]
Contribution to resolve settlement | $		$ 750
Water Provider AFFF Settlement Agreement | Forecast | Subsequent Event
Loss Contingencies [Line Items]
Settlement payment | $	$ 250							$ 500
State or U.S. Territory Attorneys General Litigation Related to AFFF
Loss Contingencies [Line Items]
Loss contingency, pending claims, number						34			34
Loss contingency, pending claims, number of states originated from | state						32			32
State or U.S. Territory Attorneys General Litigation Related to AFFF | Alaska
Loss Contingencies [Line Items]
Loss contingency, pending claims, number					2
Loss contingency, number of pending claims transferred to MDL					2
State or U.S. Territory Attorneys General Litigation Related to AFFF | North Carolina
Loss Contingencies [Line Items]
Loss contingency, pending claims, number			2	4
Loss contingency, number of pending claims transferred to MDL			2	4