v3.25.4

Summary of Significant Accounting Policies (Details) - Assets and Liabilities Classified as Held for Sale $ in Millions	Dec. 31, 2025 USD ($)
Assets
Total assets held for sale	$ 4,550
Liabilities
Total liabilities held for sale	2,542
Disposal group, held-for-sale, not discontinued operations [Member] \| Canadian insurance business excluding surety business [Member]
Assets
Fixed maturities, available for sale, at fair value	3,243
Premiums receivable	263
Reinsurance recoverables	285
Goodwill	208
Remaining assets held for sale	551
Total assets held for sale	4,550
Liabilities
Claims and claim adjustment expense reserves	1,909
Unearned premium reserves	514
Remaining liabilities held for sale	119
Total liabilities held for sale	$ 2,542

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) attributable to disposal group held for sale or disposed of.

+ References

No definition available.

+ Details

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Namespace Prefix:	trv_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, after valuation allowance, recoverable under reinsurance contracts, attributable to disposal group held for sale or disposed of.

+ References

No definition available.

+ Details

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

- Definition

Amount of unearned premium reserves attributable to disposal group held for sale.

+ References

No definition available.

+ Details

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Namespace Prefix:	trv_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount classified as assets attributable to disposal group held for sale or disposed of.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 10
-SubTopic 20
-Topic 205
-Publisher FASB
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount classified as goodwill attributable to disposal group held for sale or disposed of.

+ References

+ Details

Name:	us-gaap_DisposalGroupIncludingDiscontinuedOperationGoodwill1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of liability for claims and claims adjustment expense attributable to disposal group held for sale or disposed of.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-3

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 205
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-Publisher FASB
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
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-Publisher FASB
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- Definition

Amount classified as other assets attributable to disposal group held for sale or disposed of.

+ References

+ Details

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Balance Type:	debit
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- Definition

Amount classified as other liabilities attributable to disposal group held for sale or disposed of.

+ References

+ Details

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Balance Type:	credit
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- Definition

Amount, after allowance for credit loss, of premium receivable attributable to disposal group held for sale or disposed of.

+ References

+ Details

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Balance Type:	debit
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- Definition

Amount classified as liabilities attributable to disposal group held for sale or disposed of.

+ References

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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TRAVELERS COMPANIES, INC. 10-K