The carrying value of the assets and liabilities of the disposal group as a percentage of total assets and liabilities.

No definition available.

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- Definition

Amount relating to the capital maintenance agreement entered in connection with obtaining regulatory approval for the sale of substantially all of the disposal group. This amount is available on an as-needed basis to maintain specified surplus levels and is subject to immediate reimbursement by the counterparty.

+ References

No definition available.

+ Details

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- Definition

Contractual term relating to the capital maintenance agreement entered in connection with obtaining regulatory approval for the sale of substantially all of the disposal group.

+ References

No definition available.

+ Details

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- Definition

The investment securities proceeds associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Net of Tax

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The total number of long-term care insurance reserves held by the disposal group as a percentage of total long-term care insurance reserves.

+ References

No definition available.

+ Details

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- Definition

The potential additional sale proceeds associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The total cash and investment securities sale proceeds associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

+ References

No definition available.

+ Details

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Namespace Prefix:	afg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

The total tax benefits proceeds associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

The sum of the known and estimated amounts payable as of the balance sheet date to traditional long-term care insurance policyholders, net of reinsurance recoverables.

+ References

No definition available.

+ Details

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Namespace Prefix:	afg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Number of Long-term Care Insurance Policies.

+ References

No definition available.

+ Details

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

- Definition

Realized gains (losses) on subsidiaries.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount before tax of gain (loss) recognized on the sale or disposal of a disposal group. Excludes discontinued operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=68055307&loc=d3e2443-110228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=64862545&loc=d3e2941-110230

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Data Type:	xbrli:monetaryItemType
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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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3179-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

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

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Sale of Business (Details Textual) $ in Millions			3 Months Ended			6 Months Ended
Sale of Business (Details Textual) $ in Millions	Dec. 24, 2015 USD ($)	Mar. 31, 2015	Jun. 30, 2016 USD ($) policy	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Jun. 30, 2016 USD ($) policy	Jun. 30, 2015 USD ($)	Nov. 30, 2015
Sale of Business
Realized gains (losses) on subsidiaries			$ 2	$ 0		$ 2	$ (162)
Run-off long-term care insurance business [Member]
Sale of Business
Cash proceeds from the sale of business	$ 7
Investment securities proceeds received from the sale of business	11
Potential additional sale proceeds based on the release of certain statutory liabilities of the legal entities sold						13
Contingent capital support agreement amount	$ 35
Contingent capital support agreement term	5 years
Long-term care insurance reserves of business sold as a percentage of total long-term care insurance reserves								96.00%
Cash and investment securities proceeds from the sale of business	$ 18
Total tax benefits proceeds from the sale of business						$ 97
Loss on subsidiaries, pretax	(166)				$ (162)
Loss on subsidiaries, net of tax	$ (108)				$ (105)
Realized gains (losses) on subsidiaries			$ 2
Carrying value of the assets and liabilities of business sold as a percentage of total assets and liabilities	4.00%	4.00%
AFG [Member] \| Run-off long-term care insurance business [Member]
Sale of Business
Number of long-term care insurance policies \| policy			1,600			1,600
Long-term care insurance reserves			$ 37			$ 37