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Municipal Bond Guarantee (Tables) | 9 Months Ended
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Sep. 30, 2019
Guarantees [Abstract] |
Schedule of Municipal Bond Guarantee Insured Obligations | The following table presents a schedule of BAM’s insured obligations as of September 30, 2019 and December 31, 2018:
|  | September 30, 2019 |  | December 31, 2018
Contracts outstanding |  | 8,508 |  |  | 7,525 |
Remaining weighted average contract period outstanding (in years) |  | 10.7 |  |  | 10.7 |
Contractual debt service outstanding (in millions): |  |  |  |
Principal |  | $ | 59,190.9 |  |  | $ | 52,201.6 |
Interest |  | 30,701.7 |  |  | 26,560.3 |
Total debt service outstanding |  | $ | 89,892.6 |  |  | $ | 78,761.9 |
Gross unearned insurance premiums (in millions) |  | $ | 203.5 |  |  | $ | 176.0 |
Financial Guarantee Insurance Contracts, Premium Received over Contract Period | The following table presents a schedule of BAM’s future premium revenues as of September 30, 2019:
Millions |  | September 30, 2019
October 1, 2019 - December 31, 2019 |  | $ | 4.9 |
January 1, 2020 - March 31, 2020 |  | 4.8 |
April 1, 2020 - June 30, 2020 |  | 4.8 |
July 1, 2020 - September 30, 2020 |  | 4.6 |
October 1, 2020 - December 31, 2020 |  | 4.5 |
Total 2020 |  | 18.7 |
2021 |  | 17.4 |
2022 |  | 16.3 |
2023 |  | 15.3 |
2024 |  | 14.3 |
2025 and thereafter |  | 116.6 |
Total gross unearned insurance premiums |  | $ | 203.5 |
Schedule of Net Written Premiums | The following table presents a schedule of net written premiums included in White Mountains’s HG Global/BAM segment for the three and nine months ended September 30, 2019 and 2018:
|  | Three Months Ended September 30, |  | Nine Months Ended September 30,
Millions |  | 2019 |  | 2018 |  | 2019 |  | 2018
Written premiums: |  |  |  |  |  |  |  |
Direct |  | $ | 10.2 |  |  | $ | 3.9 |  |  | $ | 30.6 |  |  | $ | 28.9 |
Assumed |  | 10.6 |  |  | — |  |  | 10.6 |  |  | — |
Gross written premiums |  | $ | 20.8 |  |  | $ | 3.9 |  |  | $ | 41.2 |  |  | $ | 28.9 |
Earned premiums: |  |  |  |  |  |  |  |
Direct |  | $ | 4.4 |  |  | $ | 3.3 |  |  | $ | 11.9 |  |  | $ | 9.7 |
Assumed |  | .8 |  |  | — |  |  | 1.8 |  |  | — |
Gross earned premiums |  | $ | 5.2 |  |  | $ | 3.3 |  |  | $ | 13.7 |  |  | $ | 9.7 |

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- Definition Tabular disclosure of financial guarantee insurance contracts in which premiums are received over the contract period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 310 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290 + Details
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- Definition Schedule of Net Written Premiums [Table Text Block] + References No definition available. + Details
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