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SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF REGISTRANT - SUPPLEMENTARY NOTES (Details) - USD ($) | 12 Months Ended
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Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items] |  |  |
Percentage of statutory policyholders surplus used to determine maximum allowable dividends | 10.00% |  |
Adjusted statutory net income measurement period | 3 years |  |
Adjusted statutory net income dividend payment measurement period | 2 years |  |
Senior Notes | 5.25% Senior Notes due 2028 |  |  |
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items] |  |  |
Stated interest rate (in hundredths) | 5.25% |  |
Insurance Subsidiaries |  |  |
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items] |  |  |
Contributions from holding company to insurance subsidiaries | $ 0 | $ 0 | $ 0
NonInsurance Subsidiary |  |  |
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items] |  |  |
Return of capital from subsidiaries | 40,000,000 |  |
Mortgage Guaranty Insurance Corporation |  |  |
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items] |  |  |
Dividends paid to the holding company | 750,000,000 | 600,000,000 | 800,000,000
Contributions from holding company to insurance subsidiaries | $ 0 | $ 0 | $ 0

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- Definition The percentage of statutory policyholders' surplus, as defined, as of the preceding calendar year end which is used in the determination of the maximum allowable dividends that the insurance subsidiaries may pay in any twelve-month period without regulatory approval by the Office of the Commissioner of Insurance of the State of Wisconsin. + References No definition available. + Details
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- Definition Statutory Accounting Practices, Statutory Amount Available For Dividend Payments Without Regulatory Approval, Measurement, Measurement Period + References No definition available. + Details
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- Definition Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval, Measurement, Dividend Payment Period + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 16 -Paragraph Column K -Publisher SEC Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 16 -Paragraph Column J -Publisher SEC Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 16 -Paragraph Column I -Publisher SEC Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 16 -Paragraph Column H -Publisher SEC Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 16 -Paragraph Column G -Publisher SEC Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 16 -Paragraph Column F -Publisher SEC Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 16 -Paragraph Column E -Publisher SEC Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 16 -Paragraph Column D -Publisher SEC Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 16 -Paragraph Column C -Publisher SEC Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 16 -Paragraph Column B -Publisher SEC Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-X (SX) -Number 210 -Section 12 -Subsection 16 -Paragraph Column A -Publisher SEC Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column B)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477965/944-235-S99-1 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column A)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477965/944-235-S99-1 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column C)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477965/944-235-S99-1 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column D)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477965/944-235-S99-1 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column E)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477965/944-235-S99-1 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column F)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477965/944-235-S99-1 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column G)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477965/944-235-S99-1 Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column H)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477965/944-235-S99-1 Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column I)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477965/944-235-S99-1 Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column J)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477965/944-235-S99-1 Reference 22: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column K)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477965/944-235-S99-1 + Details
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