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Financial Guarantee Insurance Contracts - Summary of Gross Premium Receivable Roll-Forward (Direct and Assumed Contracts) (Detail) $ in Thousands, € in Millions, £ in Millions | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2020 EUR (€) | Mar. 31, 2020 GBP (£) | Mar. 31, 2020 USD ($) | Mar. 31, 2019 USD ($) | Jan. 01, 2020 USD ($) | Dec. 31, 2019 USD ($)
Insurance [Line Items] |  |  |  |  |  |
Allowance for Doubtful Accounts, Premiums and Other Receivables |  |  | $ 14,000 |  |  | $ 9,000
Premiums Receivable, Gross |  |  | 417,000 |  |  |
Financial Guarantee Insurance Contracts, Accelerated Premium Revenue, Amount |  |  | 187 | $ 12,000 |  |
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward] |  |  |  |  |  |
Beginning premium receivable |  |  | 416,000 | 495,000 |  |
Premium receipts |  |  | 12,000 | 13,000 |  |
Adjustments for changes in expected and contractual cash flows |  |  | 10,000 | 0 |  |
Accretion of premium receivable discount |  |  | 2,000 | 3,000 |  |
Uncollectable premiums |  |  | (2,000) |  |  |
Other adjustments (including foreign exchange) |  |  | (8,000) | 2,000 |  |
Ending premium receivable |  |  | 403,000 | $ 487,000 |  |
Premium Receivable, Allowance for Credit Loss |  |  | 14,352 |  |  |
Premium Receivable, Credit Loss Expense (Reversal) |  |  | 5,000 |  |  |
Premium Receivable, Allowance for Credit Loss, Writeoff |  |  | 0 |  |  |
Premium Receivable, Allowance for Credit Loss, Recovery |  |  | 0 |  |  |
Financing Receivable, Past Due |  |  | 1,000 |  |  |
Financing Receivable, 90 Days or More Past Due, Still Accruing |  |  | 1,000 |  |  |
United Kingdom, Pounds |  |  |  |  |  |
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward] |  |  |  |  |  |
Beginning premium receivable |  | £ 109 | 142,000 |  |  |
Ending premium receivable |  | £ 103 | 128,000 |  |  |
Euro Member Countries, Euro |  |  |  |  |  |
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward] |  |  |  |  |  |
Beginning premium receivable | € 27 |  | 30,000 |  |  |
Ending premium receivable | € 22 |  | 24,000 |  |  |
Accounting Standards Update 2016-13 [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Cumulative Effect of New Accounting Principle in Period of Adoption |  |  |  |  | $ (4,000) |
Premiums Receivable [Member] | Accounting Standards Update 2016-13 [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Cumulative Effect of New Accounting Principle in Period of Adoption |  |  |  |  | $ (3,000) |
Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 26,000 |  |  |
Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 4,000 |  |  |
Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 30,000 |  |  |
Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 18,000 |  |  |
Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 340,000 |  |  |
Structured Finance [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 70,000 |  |  |
Structured Finance [Member] | Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Structured Finance [Member] | Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 4,000 |  |  |
Structured Finance [Member] | Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 16,000 |  |  |
Structured Finance [Member] | Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 18,000 |  |  |
Structured Finance [Member] | Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 32,000 |  |  |
International Finance [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 157,000 |  |  |
International Finance [Member] | Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 13,000 |  |  |
International Finance [Member] | Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
International Finance [Member] | Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 14,000 |  |  |
International Finance [Member] | Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
International Finance [Member] | Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 130,000 |  |  |
Public Finance [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 191,000 |  |  |
Public Finance [Member] | Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 13,000 |  |  |
Public Finance [Member] | Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Public Finance [Member] | Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Public Finance [Member] | Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Public Finance [Member] | Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 178,000 |  |  |
Other Public Finance Sectors [Member] | Public Finance [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 16,000 |  |  |
Other Public Finance Sectors [Member] | Public Finance [Member] | Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Other Public Finance Sectors [Member] | Public Finance [Member] | Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Other Public Finance Sectors [Member] | Public Finance [Member] | Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Other Public Finance Sectors [Member] | Public Finance [Member] | Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Other Public Finance Sectors [Member] | Public Finance [Member] | Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 16,000 |  |  |
Other International [Member] | International Finance [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 15,000 |  |  |
Other International [Member] | International Finance [Member] | Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Other International [Member] | International Finance [Member] | Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Other International [Member] | International Finance [Member] | Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Other International [Member] | International Finance [Member] | Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Other International [Member] | International Finance [Member] | Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 15,000 |  |  |
Mortgage Backed And Home Equity [Member] | Structured Finance [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 26,000 |  |  |
Mortgage Backed And Home Equity [Member] | Structured Finance [Member] | Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Mortgage Backed And Home Equity [Member] | Structured Finance [Member] | Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 1,000 |  |  |
Mortgage Backed And Home Equity [Member] | Structured Finance [Member] | Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 3,000 |  |  |
Mortgage Backed And Home Equity [Member] | Structured Finance [Member] | Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 18,000 |  |  |
Mortgage Backed And Home Equity [Member] | Structured Finance [Member] | Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 4,000 |  |  |
Structured Insurance [Domain] | Structured Finance [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 19,000 |  |  |
Structured Insurance [Domain] | Structured Finance [Member] | Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Structured Insurance [Domain] | Structured Finance [Member] | Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Structured Insurance [Domain] | Structured Finance [Member] | Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Structured Insurance [Domain] | Structured Finance [Member] | Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Structured Insurance [Domain] | Structured Finance [Member] | Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 19,000 |  |  |
Student Loans [Member] | Structured Finance [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 19,000 |  |  |
Student Loans [Member] | Structured Finance [Member] | Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Student Loans [Member] | Structured Finance [Member] | Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 3,000 |  |  |
Student Loans [Member] | Structured Finance [Member] | Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 13,000 |  |  |
Student Loans [Member] | Structured Finance [Member] | Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Student Loans [Member] | Structured Finance [Member] | Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 4,000 |  |  |
Other Structured Finance [Member] | Structured Finance [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 6,000 |  |  |
Other Structured Finance [Member] | Structured Finance [Member] | Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Other Structured Finance [Member] | Structured Finance [Member] | Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Other Structured Finance [Member] | Structured Finance [Member] | Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Other Structured Finance [Member] | Structured Finance [Member] | Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Other Structured Finance [Member] | Structured Finance [Member] | Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 6,000 |  |  |
Sovereign And Sub Sovereign [Member] | International Finance [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 113,000 |  |  |
Sovereign And Sub Sovereign [Member] | International Finance [Member] | Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 13,000 |  |  |
Sovereign And Sub Sovereign [Member] | International Finance [Member] | Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Sovereign And Sub Sovereign [Member] | International Finance [Member] | Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 14,000 |  |  |
Sovereign And Sub Sovereign [Member] | International Finance [Member] | Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Sovereign And Sub Sovereign [Member] | International Finance [Member] | Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 86,000 |  |  |
Investor Owned And Public Utilities [Member] | International Finance [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 29,000 |  |  |
Investor Owned And Public Utilities [Member] | International Finance [Member] | Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Investor Owned And Public Utilities [Member] | International Finance [Member] | Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Investor Owned And Public Utilities [Member] | International Finance [Member] | Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Investor Owned And Public Utilities [Member] | International Finance [Member] | Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Investor Owned And Public Utilities [Member] | International Finance [Member] | Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 29,000 |  |  |
Housing Revenue [Member] | Public Finance [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 175,000 |  |  |
Housing Revenue [Member] | Public Finance [Member] | Surveillance Category Onea [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 13,000 |  |  |
Housing Revenue [Member] | Public Finance [Member] | Surveillance Category Two [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Housing Revenue [Member] | Public Finance [Member] | Surveillance Category Three [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Housing Revenue [Member] | Public Finance [Member] | Surveillance Category Four [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | 0 |  |  |
Housing Revenue [Member] | Public Finance [Member] | Surveillance Category One [Member] |  |  |  |  |  |
Insurance [Line Items] |  |  |  |  |  |
Premiums Receivable, Gross |  |  | $ 162,000 |  |  |

X
- Definition Insurance [Line Items] + References No definition available. + Details
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- Definition The valuation allowance as of the balance sheet date to reduce the gross amount of receivables to estimated net realizable value, which would be presented in parentheses on the face of the balance sheet. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524 + Details
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- Definition Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption. + References No definition available. + Details
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- Definition This element represents the amount of premium revenue on financial guarantee insurance contracts recognized during the period that was accelerated for revenue recognition purposes. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6933581&loc=SL5749298-161291 + Details
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- Definition Amount of the premium receivable for financial guarantee insurance contracts reported in the statement of financial position. This element primarily would consist of those financial guarantee insurance contracts which premiums are to be collected over the contract period, but may, on occasion, include premiums which are to be collected in full at inception, but which straddle a financial reporting 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 -Subparagraph (c)(1),(5) -URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290 + Details
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X
- Definition Amount of cash inflow from premiums received for premium receivable on financial guarantee insurance contracts. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 17 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3367-108585 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 310 -Section 50 -Paragraph 3 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290 + Details
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Balance Type: | debit
Period Type: | duration

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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
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- Definition Amount of accretion of the discount for premiums receivable on financial guarantee insurance contracts. + 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 -Subparagraph (c)(4)(iii) -URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290 + Details
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X
- Definition Amount of increase (decrease) in the premium receivable on financial guarantee insurance contracts from changes in the period of the contract. + 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 -Subparagraph (c)(4)(i) -URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290 + Details
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Balance Type: | debit
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