XML 42 R31.htm IDEA: XBRL DOCUMENT
v3.25.3

Insurance Claim Reserves (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2025
Insurance Loss Reserves [Abstract] |
Claims and claim adjustment expense reserves [Table Text Block] | Claims and claim adjustment expense reserves were as follows:
(in millions) |  | September 30, 2025 |  | December 31, 2024
Property-casualty |  | $ | 67,701 |  |  | $ | 64,088 |
Accident and health |  | 4 |  |  | 5 |
Total |  | $ | 67,705 |  |  | $ | 64,093 |
Reconciliation of beginning and ending property casualty reserve balances for claims and claim adjustment expenses [Table Text Block] | The following table presents a reconciliation of beginning and ending property casualty reserve balances for claims and claim adjustment expenses:
|  | Nine Months Ended September 30,
(in millions) |  | 2025 |  | 2024
Claims and claim adjustment expense reserves at beginning of year |  | $ | 64,088 |  |  | $ | 61,621 |
Less reinsurance recoverables on unpaid losses |  | 7,669 |  |  | 7,817 |
Net reserves at beginning of year |  | 56,419 |  |  | 53,804 |
Estimated claims and claim adjustment expenses for claims arising in the current year |  | 21,959 |  |  | 21,276 |
Estimated decrease in claims and claim adjustment expenses for claims arising in prior years |  | (648) |  |  | (321) |
Total increases |  | 21,311 |  |  | 20,955 |
Claims and claim adjustment expense payments for claims arising in: |  |  |  |
Current year |  | 7,597 |  |  | 7,255 |
Prior years |  | 10,623 |  |  | 10,545 |
Total payments |  | 18,220 |  |  | 17,800 |
Unrealized foreign exchange loss |  | 204 |  |  | 38 |
Net reserves at end of period |  | 59,714 |  |  | 56,997 |
Plus reinsurance recoverables on unpaid losses |  | 7,987 |  |  | 7,744 |
Claims and claim adjustment expense reserves at end of period |  | $ | 67,701 |  |  | $ | 64,741 |

X
- Definition Tabular disclosure of claims and claim adjustment reserves by insurance product line. + References No definition available. + Details
Name: | trv_ClaimsAndClaimAdjustmentExpenseReservesTableTextBlock
Namespace Prefix: | trv_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_InsuranceLossReservesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the activity in the reserve for settling insured claims and expenses incurred in the claims settlement process for the period. The estimated liability includes the amount of money that will be required for future payments of (a) claims that have been reported to the insurer, (b) claims related to insured events that have occurred but that have not been reported to the insurer as of the date the liability is estimated, and (c) claim adjustment expenses. Claim adjustment expenses include costs incurred in the claim settlement process such as legal fees; outside adjuster fees; and costs to record, process, and adjust claims. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480081/944-40-50-3 + Details
Name: | us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration