XML 47 R31.htm IDEA: XBRL DOCUMENT
v3.22.4

SCHEDULE I SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES | 12 Months Ended
--- | ---
Dec. 31, 2022
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract] |
Schedule I - Summary of Investments-Other Than Investments in Related Parties | WHITE MOUNTAINS INSURANCE GROUP, LTD. SUMMARY OF INVESTMENTS—OTHER THAN INVESTMENTS IN RELATED PARTIES At December 31, 2022
Millions |  | Cost |  | Carrying Value |  | Fair Value
Fixed maturity investments: |  |  |  |  |  |
U.S. Government and agency obligations |  | $ | 216.6 |  |  | $ | 206.4 |  |  | $ | 206.4 |
Debt securities issued by corporations |  | 1,098.3 |  |  | 1,018.8 |  |  | 1,018.8 |
Municipal obligations |  | 281.6 |  |  | 258.6 |  |  | 258.6 |
Mortgage and asset-backed securities |  | 288.7 |  |  | 254.2 |  |  | 254.2 |
Collateralized loan obligations |  | 190.8 |  |  | 182.9 |  |  | 182.9 |
Total fixed maturity investments |  | 2,076.0 |  |  | 1,920.9 |  |  | 1,920.9 |
Short-term investments |  | 925.2 |  |  | 924.1 |  |  | 924.1 |
Investment in MediaAlpha |  | — |  |  | 168.6 |  |  | 168.6 |
Common equity securities: |  |  |  |  |  |
Common equity securities - Industrial, Miscellaneous, and Other |  | 324.3 |  |  | 334.6 |  |  | 334.6 |
Common equity securities - Exchange traded funds |  | 336.3 |  |  | 333.8 |  |  | 333.8 |
Total common equity securities |  | 660.6 |  |  | 668.4 |  |  | 668.4 |
Other long-term investments |  | 1,340.8 |  |  | 1,488.0 |  |  | 1,488.0 |
Total investments |  | $ | 5,002.6 |  |  | $ | 5,170.0 |  |  | $ | 5,170.0 |

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

X
- Definition The entire disclosure of information about investment held by insurance company, excluding investment in related party. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 15 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -Section S99 -Paragraph 7 -Subparagraph (SX 210.12-15) -URI https://asc.fasb.org/extlink&oid=122147990&loc=d3e611379-123010 + Details
Name: | srt_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesTextBlock
Namespace Prefix: | srt_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration