Aggregate unpaid principal balance of variable interest entity loans in default

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount of variable interest entity loans in default.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Difference between aggregate unpaid principal balance and fair value of variable interest entity debt.

+ References

No definition available.

+ Details

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Namespace Prefix:	afg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Difference between aggregate unpaid principal balance and fair value of variable interest entity investments.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Face amount of managed investment entities liabilities purchased at issuance date.

+ References

No definition available.

+ Details

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Namespace Prefix:	afg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Face value of liabilities issued by managed investment entities.

+ References

No definition available.

+ Details

Name:	afg_FaceValueOfLiabilitiesIssuedByManagedInvestmentEntitiesOnIssuanceDate
Namespace Prefix:	afg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of collateralized loan obligation entities.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of collateralized loan obligation entities formed during the period.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum percentage of investment of most subordinate debt tranche of variable interest entity.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Minimum percentage of investment of most subordinate debt tranche of variable interest entity.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
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-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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+ Details

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Balance Type:	credit
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- 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

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- Details

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- Details

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- Details

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- Details

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Managed Investment Entities - Narrative (Details) $ in Millions	1 Months Ended	6 Months Ended
	May 31, 2022 USD ($) collateralizedloanobligation	Jun. 30, 2022 USD ($) collateralizedloanobligation	Dec. 31, 2021 USD ($)
Variable Interest Entity [Line Items]
Percentage of investment of most subordinate debt tranche, Minimum		7.40%
Percentage of investment of most subordinate debt tranche, Maximum		82.70%
Number of collateralized loan obligation entities \| collateralizedloanobligation		14
Difference between aggregate unpaid principal balance and fair value of CLOs' fixed maturity investments		$ 381	$ 72
Difference between aggregate unpaid principal balance and carrying value of CLOs' debt		460	187
Carrying amount of CLO loans in default		2	9
Aggregate unpaid principal balance of variable interest entity loans in default		8	18
Available for sale (AFS) fixed maturities		9,793	10,357
Number Of Collateralized Loan Obligation Entities Formed During The Period \| collateralizedloanobligation	1
Collateralized loan obligations
Variable Interest Entity [Line Items]
Available for sale (AFS) fixed maturities		1,607	1,643
Collateralized loan obligations \| Managed by third parties
Variable Interest Entity [Line Items]
Available for sale (AFS) fixed maturities		1,610	1,640
Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
Investment in CLO tranches		85	$ 76
Variable interest entity, primary beneficiary \| Subordinated Debt Obligations
Variable Interest Entity [Line Items]
Investment in CLO tranches		$ 61
New Collateralized Loan Obligation Entities
Variable Interest Entity [Line Items]
Face Value Of Liabilities Issued By Managed Investment Entities On Issuance Date	$ 404
Face Amount Of Managed Investment Entities Liabilities Purchased At Issuance Date	$ 13