XML 53 R36.htm IDEA: XBRL DOCUMENT
v3.22.0.1

SCHEDULE VI SUPPLEMENTAL INFORMATION FOR PROPERTY AND CASUALTY INSURANCE UNDERWRITERS | 12 Months Ended
--- | ---
Dec. 31, 2021
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Abstract] |
SCHEDULE VI SUPPLEMENTAL INFORMATION FOR PROPERTY AND CASUALTY INSURANCE UNDERWRITERS | WHITE MOUNTAINS INSURANCE GROUP, LTD. SUPPLEMENTAL INFORMATION FOR PROPERTY AND CASUALTY INSURANCE UNDERWRITERS (Millions)
Column A |  | Column B |  | Column C |  | Column D |  | Column E |  | Column F |  | Column G |  | Column H |  | Column I |  | Column J |  | Column K
|  | Deferred acquisition costs |  | Reserves for Unpaid Claims and Claims Adjustment Expenses |  | Discount, if any, deducted in Column C |  | Unearned Premiums |  | Earned Premiums |  | Net investment income |  | Claims and Claims Adjustment Expenses Incurred Related to |  | Amortization of deferred policy acquisition costs |  | Paid Claims and Claims Adjustment Expenses |  | Premiums written
Affiliation with registrant |  |  |  |  |  |  |  | Current Year |  | Prior Year |  |  |
Ark: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2021 |  | 100.8 |  |  | 894.7 |  |  | — |  |  | 495.9 |  |  | 637.3 |  |  | 2.9 |  |  | 336.3 |  |  | (21.5) |  |  | 111.3 |  |  | 105.5 |  |  | 859.1 |

X
- Definition The entire disclosure of supplemental information for registrant, its subsidiary and 50%-or-less-owned equity basis investee, with liability for property-casualty insurance claim. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 18 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-18) -URI http://asc.fasb.org/extlink&oid=120401096&loc=d3e575016-122915 + Details
Name: | srt_ScheduleOfSupplementalInformationForPropertyCasualtyInsuranceUnderwritersTextBlock
Namespace Prefix: | srt_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

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