v3.26.1

Cover - shares	3 Months Ended
Cover - shares	Mar. 31, 2026	May 01, 2026
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2026
Document Transition Report	false
Entity File Number	1-13653
Entity Registrant Name	AMERICAN FINANCIAL GROUP, INC.
Entity Incorporation, State or Country Code	OH
Entity Tax Identification Number	31-1544320
Entity Address, Address Line One	301 East Fourth Street
Entity Address, City or Town	Cincinnati
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	45202
City Area Code	513
Local Phone Number	579-2121
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		83,086,083
Entity Central Index Key	0001042046
Amendment Flag	false
Document Fiscal Year Focus	2026
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Common Stock
Entity Information [Line Items]
Title of 12(b) Security	Common Stock
Trading Symbol	AFG
Security Exchange Name	NYSE
5.875% Subordinated Debentures due March 2059
Entity Information [Line Items]
Title of 12(b) Security	5.875% Subordinated Debentures due March 30, 2059
Trading Symbol	AFGB
Security Exchange Name	NYSE
5.625% Subordinated Debentures due June 2060
Entity Information [Line Items]
Title of 12(b) Security	5.625% Subordinated Debentures due June 1, 2060
Trading Symbol	AFGD
Security Exchange Name	NYSE
5.125% Subordinated Debentures due December 2059
Entity Information [Line Items]
Title of 12(b) Security	5.125% Subordinated Debentures due December 15, 2059
Trading Symbol	AFGC
Security Exchange Name	NYSE
4.50% Subordinated Debentures due September 2060
Entity Information [Line Items]
Title of 12(b) Security	4.50% Subordinated Debentures due September 15, 2060
Trading Symbol	AFGE
Security Exchange Name	NYSE

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Indicate number of shares or other units outstanding of each of registrant's classes of capital or common stock or other ownership interests, if and as stated on cover of related periodic report. Where multiple classes or units exist define each class/interest by adding class of stock items such as Common Class A [Member], Common Class B [Member] or Partnership Interest [Member] onto the Instrument [Domain] of the Entity Listings, Instrument.

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Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

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AMERICAN FINANCIAL GROUP INC 10-Q