XML 161 R134.htm IDEA: XBRL DOCUMENT v3.25.0.1

Leases - ROU Assets and Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Leases [Abstract]
ROU assets	$ 60	$ 71
Lease liabilities	$ 84	$ 97
Weighted average discount rate	2.65%	2.60%
Weighted average remaining lease term	7 years 1 month 6 days	7 years 9 months 18 days

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-types1: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

- References

No definition available.

+ Details

Name:	us-gaap_LeasesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration