Contingencies - Estimate Timing of Cash Outflows on Environmental Reserves (Detail) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
2025 (excluding the six months ended June 30, 2025)	$ 9
2026 - 2030	172
Thereafter	74
Total	$ 255	$ 220	$ 268

Accrual for environmental loss contingencies undiscounted one to five year.

No definition available.

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- Definition

Total costs accrued as of the balance sheet date for environmental loss contingencies.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1

Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 410
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Subparagraph (d)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481931/410-30-50-10

Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Topic 410
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Subparagraph (d)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481931/410-30-50-10

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 410
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 16
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481899/410-30-55-16

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.Y.Q1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480102/450-20-S99-1

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 410
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481931/410-30-50-7

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Undiscounted amount of accrual for environmental loss contingency to be paid after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.Y.Q1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480102/450-20-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 410
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481931/410-30-50-7

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Undiscounted amount of accrual for environmental loss contingency to be paid in remainder of current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.Y.Q1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480102/450-20-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 410
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481931/410-30-50-7

+ Details

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Period Type:	instant

- References

No definition available.

+ Details

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