v3.26.1

Investments (Details) - Allowance for Expected Credit Losses - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Allowance for expected credit losses [Roll Forward]
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, beginning of period	$ 3
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, end of period	3
Total net impairment charges, including credit impairments, reported in net realized investment gains (losses) in the consolidated statement of income	$ 4	$ 2
Credit losses on fixed maturities recognized in the consolidated statement of income, as a percentage of the fixed maturity portfolio on a pre-tax basis (less than)	1.00%	1.00%
Credit losses on fixed maturities recognized in the consolidated statement of income, as a percentage of shareholders' equity on an after-tax basis (less than)	1.00%	1.00%
Corporate and all other bonds [Member]
Allowance for expected credit losses [Roll Forward]
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, beginning of period	$ 3	$ 2
Additions for expected credit losses on securities where no credit losses were previously recognized	0	2
Additions (reductions) for expected credit losses on securities where credit losses were previously recognized	0	0
Reductions due to sales/defaults of credit-impaired securities	0	0
Reductions for impairments of securities which the Company intends to sell or more likely than not will be required to sell	0	0
Allowance for expected credit losses on fixed maturities classified as available-for-sale, balance, end of period	$ 3	$ 4

Credit losses recognized in earnings during the period related to debt securities held, as a percentage of the fixed maturity portfolio on a pretax basis.

+ References

No definition available.

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- Definition

Credit losses recognized in earnings during the period related to debt securities held, as a percentage of shareholders' equity on an after-tax basis.

+ References

No definition available.

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- Definition

Total amount of net impairment changes, including credit impairments, reported in net realized investment gains (losses) in the consolidated statement of income.

+ References

No definition available.

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- Definition

Amount of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aaa)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

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- Definition

Amount of expense for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), for which no credit loss was previously recorded.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476148/220-40-50-22

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- Definition

Amount of expense (reversal of expense) for allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), not intended to be sold and not more likely than not will be required to sell before recovery of amortized cost basis, with previously recorded allowance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476148/220-40-50-22

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

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- Definition

Amount of decrease in allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) from intent to sell or more likely than not will be required to sell before recovery of amortized cost basis.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

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TRAVELERS COMPANIES, INC. 10-Q