XML 160 R144.htm IDEA: XBRL DOCUMENT
v3.22.4

Leases - Narrative (Details) ft² in Thousands, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2022 USD ($) ft² | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($)
Lessee, Lease, Description [Line Items] |  |  |
Lease space | ft² | 271 |  |
Total lease assets | $ 87 | $ 100 |
Total lease liability | $ 116 | $ 136 |
Weighted average remaining lease term | 8 years 2 months 12 days | 8 years 7 months 6 days |
Weighted average discount rate | 2.49% | 2.40% |
ROU asset impairment |  |  | $ 13

X
- Definition Finance and Operating Lease, Weighted Average Discount Rate, Percent + References No definition available. + Details
Name: | ago_FinanceAndOperatingLeaseWeightedAverageDiscountRatePercent
Namespace Prefix: | ago_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Finance and Operating Lease, Weighted Average Remaining Lease Term + References No definition available. + Details
Name: | ago_FinanceAndOperatingLeaseWeightedAverageRemainingLeaseTerm
Namespace Prefix: | ago_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Finance and Operating Lease, Liability + References No definition available. + Details
Name: | ago_FinanceandOperatingLeaseLiability
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Finance and Operating Lease, Right-of-Use Asset + References No definition available. + Details
Name: | ago_FinanceandOperatingLeaseRightofUseAsset
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Operating Leases, Rented Area + References No definition available. + Details
Name: | ago_OperatingLeasesRentedArea
Namespace Prefix: | ago_
Data Type: | dtr-types:areaItemType
Balance Type: | na
Period Type: | instant

X
- 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 No definition available. + Details
Name: | us-gaap_LesseeLeaseDescriptionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of loss from impairment of right-of-use asset from operating lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 25 -Paragraph 6 -Subparagraph (c) -URI https://asc.fasb.org/extlink&oid=123399704&loc=SL77918431-209957 + Details
Name: | us-gaap_OperatingLeaseImpairmentLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration