Represents the debt instrument’s issuance price as a percentage of the debt instrument's face amount.

No definition available.

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- Definition

Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing after the sixth fiscal year following the latest fiscal year.

+ References

No definition available.

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Amount of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates maturing in the sixth fiscal year following the latest fiscal year ended.

+ References

No definition available.

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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No definition available.

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Face (par) amount of debt instrument at time of issuance.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-SubTopic 30
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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

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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.

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No definition available.

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- Definition

Face (par) amount of the original debt instrument that was repurchased.

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No definition available.

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- Definition

The percentage points added to the reference rate to compute the variable rate on the interest rate derivative.

+ References

No definition available.

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- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

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Contains all pertinent information about an entity's fair value hedging activities.

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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- Definition

Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions).

+ References

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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- References

No definition available.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-SubTopic 10
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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the remainder of the fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Long-Term Debt - Narrative (Details) - USD ($)		9 Months Ended
Long-Term Debt - Narrative (Details) - USD ($)	Jun. 30, 2017	Sep. 30, 2017	Aug. 25, 2017	Dec. 31, 2016
Long-term Debt, Fiscal Year Maturity [Abstract]
Scheduled principal payments on debt in 2017		$ 0
Scheduled principal payments on debt in 2018		0
Scheduled principal payments on debt in 2019		350,000,000
Scheduled principal payments on debt in 2020		0
Scheduled principal payments on debt in 2021		0
Scheduled principal payments on debt in 2022		0
Scheduled principal payments on debt after 2022		953,000,000
AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Revolving credit line		500,000,000
Amount borrowed under revolving credit facility		$ 0		$ 0
Interest rate description of fair value hedge activity		three-month LIBOR plus 8.099%
Interest rate description for revolving credit facility		1.00% to 1.875% (currently 1.375%) over LIBOR
LIBOR \| AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Interest rate on revolving debt facility	1.375%
LIBOR \| AFG \| Minimum
Long-term Debt, Fiscal Year Maturity [Abstract]
Interest rate on revolving debt facility	1.00%
LIBOR \| AFG \| Maximum
Long-term Debt, Fiscal Year Maturity [Abstract]
Interest rate on revolving debt facility	1.875%
Interest rate swaps \| Fair Value Hedge \| Designated as Hedging Instrument \| AFG
Debt Instrument [Line Items]
Effective interest rate, percentage		9.419%		9.0624%
Interest rate swaps \| Fair Value Hedge \| Designated as Hedging Instrument \| LIBOR \| AFG
Debt Instrument [Line Items]
Basis spread on variable interest rate		8.099%
Long-term debt \| Interest rate swaps \| Fair Value Hedge \| Designated as Hedging Instrument \| AFG
Debt Instrument [Line Items]
Net derivatives, at fair value				$ 1,000,000
Long-term debt \| Interest rate swaps \| Fair Value Hedge \| Designated as Hedging Instrument \| AFG \| Maximum
Debt Instrument [Line Items]
Net derivatives, at fair value		$ (1,000,000)
Senior Notes \| 9-7/8% Senior Notes due June 2019
Long-term Debt, Fiscal Year Maturity [Abstract]
Stated interest rate, percentage		9.875%
Senior Notes \| 9-7/8% Senior Notes due June 2019 \| AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Stated interest rate, percentage		9.875%		9.875%
Senior Notes \| 4.50% Senior Notes due June 2047 \| AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Senior Notes, aggregate principal amount	$ 350,000,000
Stated interest rate, percentage	4.50%	4.50%
Senior Notes, issuance price as a percentage of par value	99.46%
Senior Notes \| 3.50% Senior Notes due August 2026 \| AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Stated interest rate, percentage		3.50%
Senior Notes \| 6-3/8% Senior Notes due June 2042 \| AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Stated interest rate, percentage		6.375%
Senior Notes, amount of the original debt instrument that was redeemed	$ 230,000,000
Senior Notes \| 5-3/4% Senior Notes due August 2042 \| AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Stated interest rate, percentage		5.75%
Senior Notes, amount of the original debt instrument that was redeemed			$ 125,000,000
Subordinated Debentures \| 6-1/4% Subordinated Debentures due September 2054 \| AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Stated interest rate, percentage		6.25%
Subordinated Debentures \| 6% Subordinated Debentures due November 2055 \| AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Stated interest rate, percentage		6.00%