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Municipal Bond Guarantee (Tables) | 6 Months Ended
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Jun. 30, 2019
Guarantees [Abstract] |
Schedule of Municipal Bond Guarantee Insured Obligations | The following table presents a schedule of BAM’s insured obligations as of June 30, 2019 and December 31, 2018:
|  | June 30, 2019 |  | December 31, 2018
Contracts outstanding |  | 8,126 |  |  | 7,525 |
Remaining weighted average contract period outstanding (in years) |  | 10.8 |  |  | 10.7 |
Contractual debt service outstanding (in millions): |  |  |  |
Principal |  | $ | 56,043.9 |  |  | $ | 52,201.6 |
Interest |  | 28,591.7 |  |  | 26,560.3 |
Total debt service outstanding |  | $ | 84,635.6 |  |  | $ | 78,761.9 |
Gross unearned insurance premiums |  | $ | 187.8 |  |  | $ | 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 June 30, 2019:
Millions |  | June 30, 2019
July 1, 2019 - December 31, 2019 |  | $ | 8.5 |
January 1, 2020 - March 31, 2020 |  | 4.1 |
April 1, 2020 - June 30, 2020 |  | 4.1 |
July 1, 2020 - September 30, 2020 |  | 4.0 |
October 1, 2020 - December 31, 2020 |  | 4.0 |
Total 2020 |  | 16.2 |
2021 |  | 15.3 |
2022 |  | 14.4 |
2023 |  | 13.6 |
2024 |  | 12.8 |
2025 and thereafter |  | 107.0 |
Total gross unearned insurance premiums |  | $ | 187.8 |
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 six months ended June 30, 2019 and 2018:
|  | Three Months Ended June 30, |  | Six Months Ended June 30,
Millions |  | 2019 |  | 2018 |  | 2019 |  | 2018
Written premiums: |  |  |  |  |  |  |  |
Direct |  | $ | 12.5 |  |  | $ | 18.6 |  |  | $ | 20.4 |  |  | $ | 25.0 |
Assumed |  | — |  |  | — |  |  | — |  |  | — |
Gross written premiums |  | $ | 12.5 |  |  | $ | 18.6 |  |  | $ | 20.4 |  |  | $ | 25.0 |
Earned premiums: |  |  |  |  |  |  |  |
Direct |  | $ | 3.8 |  |  | $ | 3.4 |  |  | $ | 7.5 |  |  | $ | 6.4 |
Assumed |  | .5 |  |  | — |  |  | 1.0 |  |  | — |
Gross earned premiums |  | $ | 4.3 |  |  | $ | 3.4 |  |  | $ | 8.5 |  |  | $ | 6.4 |

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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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