XML 71 R48.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Basis of Presentation and Significant Accounting Policies FX gain (loss) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Foreign Currency Transaction Gain (Loss), before Tax | $ 12 | $ (7) | $ 21
Premiums Receivable [Member] |  |  |
Foreign Currency Transaction Gain (Loss), before Tax | (10) | 2 | (2)
Lossandlossreserves [Member] |  |  |
Foreign Currency Transaction Gain (Loss), before Tax | (1) | (15) | 29
Gain (Loss) on Investments [Member] |  |  |
Foreign Currency Transaction Gain (Loss), before Tax | $ 22 | $ 7 | $ (5)

X
- Definition Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109240200&loc=d3e30700-110894 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=109240200&loc=d3e30690-110894 + Details
Name: | us-gaap_ForeignCurrencyTransactionGainLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_PremiumsReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=ambc_LossandlossreservesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_GainLossOnInvestmentsMember1
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |