American Financial (AFG) 10-K 26 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Billions, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 01, 2015	Jun. 30, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	AMERICAN FINANCIAL GROUP INC
Entity Central Index Key	1042046
Document Type	10-K
Document Period End Date	31-Dec-14
Amendment Flag	FALSE
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$4.60
Entity Common Stock, Shares Outstanding		87,255,891

Consolidated_Balance_Sheet

Consolidated Balance Sheet (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Assets:
Cash and cash equivalents	$1,343	$1,639
Investments:
Fixed maturities, available for sale at fair value (amortized cost — $29,074 and $25,366)	30,734	26,456
Fixed maturities, trading at fair value	266	305
Equity securities, available for sale at fair value (cost — $1,283 and $931)	1,501	1,123
Equity securities, trading at fair value	195	56
Mortgage loans	1,117	781
Policy loans	228	238
Real estate and other investments	826	715
Total cash and investments	36,210	31,313
Recoverables from reinsurers	3,238	3,157
Prepaid reinsurance premiums	469	408
Agents’ balances and premiums receivable	889	739
Deferred policy acquisition costs	821	975
Assets of managed investment entities	3,108	2,888
Other receivables	910	854
Variable annuity assets (separate accounts)	662	665
Other assets	1,027	903
Goodwill	201	185
Total assets	47,535	42,087
Liabilities and Equity:
Unpaid losses and loss adjustment expenses	7,872	6,410
Unearned premiums	1,956	1,757
Annuity benefits accumulated	23,764	20,944
Life, accident and health reserves	2,175	2,008
Payable to reinsurers	645	508
Liabilities of managed investment entities	2,819	2,567
Long-term debt	1,061	913
Variable annuity liabilities (separate accounts)	662	665
Other liabilities	1,527	1,546
Total liabilities	42,481	37,318
Shareholders’ equity:
Common Stock, no par value — 200,000,000 shares authorized — 87,708,793 and 89,513,386 shares outstanding	88	90
Capital surplus	1,152	1,123
Retained earnings:
Appropriated — managed investment entities	-2	49
Unappropriated	2,914	2,777
Accumulated other comprehensive income, net of tax	727	560
Total shareholders’ equity	4,879	4,599
Noncontrolling interests	175	170
Total equity	5,054	4,769
Total liabilities and equity	$47,535	$42,087

Consolidated_Balance_Sheet_Par

Consolidated Balance Sheet (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Fixed maturities, available for sale at amortized cost	$29,074	$25,366
Equity securities, available for sale at cost	$1,283	$931
Common Stock, par value (USD per share)	$0	$0
Common Stock, shares authorized	200,000,000	200,000,000
Common Stock, shares outstanding	87,708,793	89,513,386

Consolidated_Statement_of_Earn

Consolidated Statement of Earnings (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Property and casualty insurance net earned premiums	$3,878	$3,204	$2,847
Life, accident and health net earned premiums	108	114	318
Net investment income	1,501	1,346	1,301
Realized gains (losses) on:
Securities	52	221	210
Subsidiaries	0	-4	161
Income (loss) of managed investment entities:
Investment income	116	128	125
Loss on change in fair value of assets/liabilities	-44	-14	-94
Other income	102	97	89
Total revenues	5,713	5,092	4,957
Costs and Expenses:
Property and casualty insurance: Losses and loss adjustment expenses	2,494	2,040	1,873
Property and casualty insurance: Commissions and other underwriting expenses	1,172	1,019	887
Annuity benefits	648	531	541
Life, accident and health benefits	164	160	356
Annuity and supplemental insurance acquisition expenses	173	167	282
Interest charges on borrowed money	73	71	75
Expenses of managed investment entities	82	89	80
Other expenses	281	326	326
Total costs and expenses	5,087	4,403	4,420
Earnings before income taxes	626	689	537
Provision for income taxes	220	236	135
Net earnings, including noncontrolling interests	406	453	402
Less: Net earnings (loss) attributable to noncontrolling interests	-46	-18	-86
Net Earnings Attributable to Shareholders	452	471	488
Earnings Attributable to Shareholders per Common Share:
Basic (USD per share)	$5.07	$5.27	$5.18
Diluted (USD per share)	$4.97	$5.16	$5.09
Average number of Common Shares:
Basic (shares)	89	89.3	94.2
Diluted (shares)	91	91.2	95.9
Cash dividends per Common Share (USD per share)	$1.91	$1.81	$0.97
Supplemental disclosure of Realized gains (losses) on securities:
Realized gains before impairments	88	233	236
Losses on securities with impairment	-36	-14	-27
Non-credit portion recognized in other comprehensive income (loss)	0	2	1
Impairment charges recognized in earnings	-36	-12	-26
Total realized gains on securities	$52	$221	$210

Consolidated_Statement_of_Comp

Consolidated Statement of Comprehensive Income (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net earnings, including noncontrolling interests	$406	$453	$402
Net unrealized gains (losses) on securities:
Unrealized holding gains (losses) on securities arising during the period	216	-122	408
Reclassification adjustment for realized gains included in net earnings	-33	-144	-138
Reclassification adjustment for unrealized gains of subsidiaries sold	0	0	-18
Total net unrealized gains (losses) on securities	183	-266	252
Foreign currency translation adjustments	-9	-13	6
Pension and other postretirement plans adjustments	-4	2	2
Other comprehensive income (loss), net of tax	170	-277	260
Total comprehensive income, net of tax	576	176	662
Less: Comprehensive income (loss) attributable to noncontrolling interests	-43	-24	-78
Comprehensive income attributable to shareholders	$619	$200	$740

Consolidated_Statement_of_Chan

Consolidated Statement of Changes in Equity (USD $)	Total	Common Shares	Common Stock and Capital Surplus	Retained Earnings Approp.	Retained Earnings Unapprop.	Accumulated Other Comprehensive Inc. (Loss)	Total	Noncontrolling Interests
In Millions, except Share data, unless otherwise specified	USD ($)		USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)
Beginning Balance at Dec. 31, 2011	$4,557		$1,219	$173	$2,439	$580	$4,411	$146
Beginning Balance, shares at Dec. 31, 2011		97,846,402
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	402				488		488	-86
Other comprehensive income (loss)	260					252	252	8
Allocation of losses of managed investment entities	0			-98			-98	98
Dividends on Common Stock	-91				-91		-91
Shares issued:
Exercise of stock options, shares		1,702,782
Exercise of stock options	45		45				45
Other benefit plans, shares		308,352
Other benefit plans	7		7				7
Dividend reinvestment plan, shares		21,484
Dividend reinvestment plan	1		1				1
Stock-based compensation expense	18		18				18
Shares acquired and retired, shares		-10,864,184
Shares acquired and retired	-415		-137		-278		-415
Shares exchanged - benefit plans, shares		-35,533
Shares exchanged - benefit plans	-1		-1				-1
Other	-35				-38	-1	-39	4
Ending Balance at Dec. 31, 2012	4,748		1,152	75	2,520	831	4,578	170
Ending Balance, shares at Dec. 31, 2012		88,979,303
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	453				471		471	-18
Other comprehensive income (loss)	-277					-271	-271	-6
Allocation of losses of managed investment entities	0			-26			-26	26
Dividends on Common Stock	-161				-161		-161
Shares issued:
Exercise of stock options, shares		1,625,023
Exercise of stock options	53		53				53
Other benefit plans, shares		388,043
Other benefit plans	7		7				7
Dividend reinvestment plan, shares		28,147
Dividend reinvestment plan	2		2				2
Stock-based compensation expense	19		19				19
Shares acquired and retired, shares		-1,448,156
Shares acquired and retired	-70		-19		-51		-70
Shares exchanged - benefit plans, shares		-58,974
Shares exchanged - benefit plans	-3		-1		-2		-3
Other	-2				0	0	0	-2
Ending Balance at Dec. 31, 2013	4,769		1,213	49	2,777	560	4,599	170
Ending Balance, shares at Dec. 31, 2013	89,513,386	89,513,386
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	406				452		452	-46
Other comprehensive income (loss)	170					167	167	3
Allocation of losses of managed investment entities	0			-51			-51	51
Dividends on Common Stock	-169				-169		-169
Shares issued:
Exercise of stock options, shares	1,262,313	1,262,313
Exercise of stock options	45		45				45
Other benefit plans, shares		242,669
Other benefit plans	8		8				8
Dividend reinvestment plan, shares		27,238
Dividend reinvestment plan	2		2				2
Stock-based compensation expense	19		19				19
Shares acquired and retired, shares		-3,303,639
Shares acquired and retired	-191		-46		-145		-191
Shares exchanged - benefit plans, shares		-33,174
Shares exchanged - benefit plans	-2		-1		-1		-2
Other	-3							-3
Ending Balance at Dec. 31, 2014	$5,054		$1,240	($2)	$2,914	$727	$4,879	$175
Ending Balance, shares at Dec. 31, 2014	87,708,793	87,708,793

Consolidated_Statement_of_Cash

Consolidated Statement of Cash Flows (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Activities:
Net earnings, including noncontrolling interests	$406	$453	$402
Adjustments:
Depreciation and amortization	144	142	257
Annuity benefits	648	531	541
Realized gains on investing activities	-58	-230	-367
Net (purchases) sales of trading securities	-109	2	17
Deferred annuity and life policy acquisition costs	-198	-222	-212
Change in:
Reinsurance and other receivables	-199	176	-495
Other assets	-87	-149	-51
Insurance claims and reserves	587	-200	918
Payable to reinsurers	134	51	0
Other liabilities	-63	280	-180
Managed investment entities’ assets/liabilities	2	-98	-21
Other operating activities, net	15	24	8
Net cash provided by operating activities	1,222	760	817
Investing Activities:
Purchases of fixed maturities	-6,846	-6,690	-4,458
Purchases of equity securities	-471	-461	-281
Purchases of mortgage loans	-450	-274	-269
Purchases of real estate, property and equipment	-47	-52	-71
Purchases of businesses	-267	0	0
Proceeds from maturities and redemptions of fixed maturities	2,988	3,236	2,262
Proceeds from repayments of mortgage loans	116	102	46
Proceeds from sales of fixed maturities	287	275	632
Proceeds from sales of equity securities	155	434	437
Proceeds from sales of real estate, property and equipment	14	34	4
Proceeds from sales of businesses	0	0	322
Cash and cash equivalents of businesses acquired (sold)	1,078	-5	-34
Managed investment entities:
Purchases of investments	-1,692	-1,426	-1,849
Proceeds from sales and redemptions of investments	1,417	1,904	1,857
Other investing activities, net	99	8	-23
Net cash used in investing activities	-3,619	-2,915	-1,425
Financing Activities:
Annuity receipts	3,696	4,233	2,993
Annuity surrenders, benefits and withdrawals	-1,773	-1,588	-1,504
Net transfers from variable annuity assets	43	32	36
Additional long-term borrowings	145	0	372
Reductions of long-term debt	-2	-40	-365
Issuances of managed investment entities’ liabilities	1,400	1,192	781
Retirement of managed investment entities’ liabilities	-1,094	-1,560	-830
Issuances of Common Stock	47	54	46
Repurchases of Common Stock	-191	-70	-415
Cash dividends paid on Common Stock	-167	-160	-90
Other financing activities, net	-3	-4	-35
Net cash provided by (used in) financing activities	2,101	2,089	989
Net Change in Cash and Cash Equivalents	-296	-66	381
Cash and cash equivalents at beginning of year	1,639	1,705	1,324
Cash and cash equivalents at end of year	$1,343	$1,639	$1,705

Accounting_Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Accounting Policies	Accounting Policies
	Basis of Presentation   The consolidated financial statements include the accounts of American Financial Group, Inc. (“AFG”) and its subsidiaries. Certain reclassifications have been made to prior years to conform to the current year’s presentation. All significant intercompany balances and transactions have been eliminated. The results of operations of companies since their formation or acquisition are included in the consolidated financial statements. Events or transactions occurring subsequent to December 31, 2014, and prior to the filing of this Form 10-K, have been evaluated for potential recognition or disclosure herein.
	The preparation of the financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Changes in circumstances could cause actual results to differ materially from those estimates.
	Fair Value Measurements   Accounting standards define fair value as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants on the measurement date. The standards establish a hierarchy of valuation techniques based on whether the assumptions that market participants would use in pricing the asset or liability (“inputs”) are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect AFG’s assumptions about the assumptions market participants would use in pricing the asset or liability. Other than the recording of the acquisition of Summit Holding Southeast, Inc. and its related companies (see Note B — “Acquisitions and Sales of Businesses”), AFG did not have any significant nonrecurring fair value measurements of nonfinancial assets and liabilities in 2014 or 2013.
	Investments   Fixed maturity and equity securities classified as “available for sale” are reported at fair value with unrealized gains and losses included in accumulated other comprehensive income (“AOCI”) in AFG’s Balance Sheet. Fixed maturity and equity securities classified as “trading” are reported at fair value with changes in unrealized holding gains or losses during the period included in net investment income. Mortgage and policy loans are carried primarily at the aggregate unpaid balance.
	Premiums and discounts on fixed maturity securities are amortized using the interest method; mortgage-backed securities (“MBS”) are amortized over a period based on estimated future principal payments, including prepayments. Prepayment assumptions are reviewed periodically and adjusted to reflect actual prepayments and changes in expectations.
	Gains or losses on securities are determined on the specific identification basis. When a decline in the value of a specific investment is considered to be other-than-temporary at the balance sheet date, a provision for impairment is charged to earnings (included in realized gains (losses) on securities) and the cost basis of that investment is reduced. If management can assert that it does not intend to sell an impaired fixed maturity security and it is not more likely than not that it will have to sell the security before recovery of its amortized cost basis, then the other-than-temporary impairment is separated into two components: (i) the amount related to credit losses (recorded in earnings) and (ii) the amount related to all other factors (recorded in other comprehensive income). The credit-related portion of an other-than-temporary impairment is measured by comparing a security’s amortized cost to the present value of its current expected cash flows discounted at its effective yield prior to the impairment charge. Both components are shown in the Statement of Earnings. If management intends to sell an impaired security, or it is more likely than not that it will be required to sell the security before recovery, an impairment charge to earnings is recorded to reduce the amortized cost of that security to fair value.
	Derivatives   Derivatives included in AFG’s Balance Sheet are recorded at fair value. Changes in fair value of derivatives are included in earnings, unless the derivatives are designated as cash flow hedges. Derivatives that do not qualify for hedge accounting under GAAP consist primarily of (i) components of certain fixed maturity securities (primarily interest-only MBS) and (ii) the equity-based component of certain annuity products (included in annuity benefits accumulated) and related call options (included in other investments) designed to be consistent with the characteristics of the liabilities and used to mitigate the risk embedded in those annuity products.
	To qualify for hedge accounting, at the inception of a derivative contract, AFG formally documents the relationship between the terms of the hedge and the hedged items and its risk management objective. This documentation includes defining how hedge effectiveness and ineffectiveness will be measured on a retrospective and prospective basis. Changes in the fair value of derivatives that are designated and qualify as highly effective cash flow hedges are recorded in AOCI and are reclassified into earnings when the variability of the cash flows from the hedged items impact earnings. Any hedge ineffectiveness is immediately recorded in current period earnings. When the change in the fair value of a qualifying cash flow hedge is included in earnings, it is included in the same line item in the Consolidated Statement of Earnings as the cash flows from the hedged item. Qualifying highly effective cash flow hedges include interest rate swaps, which are used to mitigate interest rate risk related to certain floating-rate securities included in AFG’s portfolio of fixed maturity securities.
	Goodwill   Goodwill represents the excess of cost of subsidiaries over AFG’s equity in their underlying net assets. Goodwill is not amortized, but is subject to an impairment test at least annually. An entity is not required to complete the quantitative annual goodwill impairment test on a reporting unit if the entity elects to perform a qualitative analysis and determines that it is more likely than not that the reporting unit’s fair value exceeds its carrying amount.
	Reinsurance   Amounts recoverable from reinsurers are estimated in a manner consistent with the claim liability associated with the reinsured policies. AFG’s property and casualty insurance subsidiaries report as assets (i) the estimated reinsurance recoverable on paid and unpaid losses, including an estimate for losses incurred but not reported, and (ii) amounts paid or due to reinsurers applicable to the unexpired terms of policies in force. Payable to reinsurers includes ceded premiums due to reinsurers as well as ceded premiums retained by AFG’s property and casualty insurance subsidiaries under contracts to fund ceded losses as they become due. AFG’s insurance subsidiaries also assume reinsurance from other companies. Earnings on reinsurance assumed is recognized based on information received from ceding companies.
	A subsidiary cedes life insurance policies to a third party on a funds withheld basis whereby the subsidiary retains the assets (securities) associated with the reinsurance contract. Interest is credited to the reinsurer based on the actual investment performance of the retained assets. This reinsurance contract is considered to contain an embedded derivative (that must be adjusted to fair value) because the yield on the payable is based on a specific block of the ceding company’s assets, rather than the overall creditworthiness of the ceding company. AFG determined that changes in the fair value of the underlying portfolio of fixed maturity securities is an appropriate measure of the value of the embedded derivative. The securities related to this contract are classified as “trading.” The adjustment to fair value on the embedded derivative offsets the investment income recorded on the adjustment to fair value of the related trading portfolio.
	Deferred Policy Acquisition Costs (“DPAC”)   Policy acquisition costs (principally commissions, premium taxes and certain underwriting and policy issuance costs) directly related to the successful acquisition or renewal of an insurance contract are deferred. DPAC also includes capitalized costs associated with sales inducements offered to fixed annuity policyholders such as enhanced interest rates and premium and persistency bonuses.
	For the property and casualty companies, DPAC is limited based upon recoverability without any consideration for anticipated investment income and is charged against income ratably over the terms of the related policies. A premium deficiency is recognized if the sum of expected claims costs, claims adjustment expenses and unamortized acquisition costs exceed the related unearned premiums. A premium deficiency is first recognized by charging any unamortized acquisition costs to expense to the extent required to eliminate the deficiency. If the premium deficiency is greater than unamortized acquisition costs, a liability is accrued for the excess deficiency and reported with unpaid losses and loss adjustment expenses.
	DPAC related to annuities is deferred to the extent deemed recoverable and amortized, with interest, in relation to the present value of actual and expected gross profits on the policies. Expected gross profits consist principally of estimated future investment margin (estimated future net investment income less interest credited on policyholder funds) and surrender, mortality, and other life and annuity policy charges, less death, annuitization and guaranteed withdrawal benefits in excess of account balances and estimated future policy administration expenses. To the extent that realized gains and losses result in adjustments to the amortization of DPAC related to annuities, such adjustments are reflected as components of realized gains (losses) on securities.
	DPAC related to traditional life and health insurance is amortized over the expected premium paying period of the related policies, in proportion to the ratio of annual premium revenues to total anticipated premium revenues. See “Life, Accident and Health Reserves” below for details on the impact of loss recognition on the accounting for traditional life and health insurance contracts.
	DPAC includes the present value of future profits on business in force of annuity and life, accident and health insurance companies acquired (“PVFP”). PVFP represents the portion of the costs to acquire companies that is allocated to the value of the right to receive future cash flows from insurance contracts existing at the date of acquisition. PVFP is amortized with interest in relation to expected gross profits of the acquired policies for annuities and universal life products and in relation to the premium paying period for traditional life and health insurance products.
	DPAC and certain other balance sheet amounts related to annuity, long-term care and life businesses are also adjusted, net of tax, for the change in expense that would have been recorded if the unrealized gains (losses) from securities had actually been realized. These adjustments are included in unrealized gains (losses) on marketable securities, a component of AOCI in AFG’s Balance Sheet.
	Managed Investment Entities   A company is considered the primary beneficiary of, and therefore must consolidate, a variable interest entity (“VIE”) based primarily on its ability to direct the activities of the VIE that most significantly impact that entity’s economic performance and the obligation to absorb losses of, or receive benefits from, the entity that could potentially be significant to the VIE.
	AFG manages, and has investments in, collateralized loan obligations (“CLOs”) that are VIEs (see Note H — “Managed Investment Entities”). Both the management fees (payment of which is subordinate to other obligations of the CLOs) and the investments in the CLOs are considered variable interests. AFG has determined that it is the primary beneficiary of the CLOs because (i) its role as asset manager gives it the power to direct the activities that most significantly impact the economic performance of the CLOs and (ii) it has exposure to CLO losses (through its investments in the CLO debt tranches) and the right to receive benefits (through its subordinated management fees and returns on its investments), both of which could potentially be significant to the CLOs.
	Because AFG has no right to use the CLO assets and no obligation to pay the CLO liabilities, the assets and liabilities of the CLOs are shown separately in AFG’s Balance Sheet (at fair value). AFG has elected the fair value option for reporting on the CLO assets and liabilities to improve the transparency of financial reporting related to the CLOs. The excess of fair value of the CLOs’ assets over the fair value of the liabilities is recorded in AFG’s Balance Sheet as appropriated retained earnings — managed investment entities, representing amounts that ultimately will inure to the CLO debt holders.
	The net gain or loss from accounting for the CLO assets and liabilities at fair value is separately presented in AFG’s Statement of Earnings. CLO earnings attributable to AFG’s shareholders represent the change in fair value of AFG’s investments in the CLOs (including distributions) and management fees earned. All other CLO earnings (losses) are not attributable to AFG’s shareholders and will ultimately inure to the CLO debt holders. As a result, such CLO earnings (losses) are included in net earnings (loss) attributable to noncontrolling interests in AFG’s Statement of Earnings and in appropriated retained earnings — managed investment entities in the Balance Sheet. As the CLOs approach maturity (2016 to 2026), it is expected that earnings (losses) attributable to noncontrolling interests will reduce appropriated retained earnings towards zero as the fair values of the assets and liabilities converge and the CLO assets are used to pay the CLO debt.
	At December 31, 2014, assets and liabilities of managed investment entities included $17 million in assets and $12 million in liabilities of a temporary warehousing entity that was established in connection with the formation of a new CLO that is expected to close in the second quarter of 2015. Upon closing, all warehoused assets are expected to be transferred to the new CLO and the liabilities will be repaid.
	In August 2014, the FASB issued Accounting Standards Update (“ASU”) 2014-13 to address the diversity in practice regarding the accounting for assets and liabilities of a consolidated collateralized financing entity (such as a CLO) when an election has been made to account for that entity’s assets and liabilities at fair value. As discussed above, the fair values of a CLO’s assets may differ from the fair values of its liabilities even though the liabilities only have recourse to the assets, which results in “appropriated retained earnings — managed investment entities” in AFG’s Balance Sheet. Under ASU 2014-13, AFG will have the option to set the carrying value of the CLO liabilities equal to the fair value of the CLO assets (which have more observable fair values) as an alternative to reporting those liabilities at fair value. Under this alternative, CLO earnings attributable to AFG’s shareholders would continue to be measured by the change in the fair value of AFG’s investments in the CLOs and management fees earned. However, as a result of setting the carrying value of the CLO liabilities equal to the fair value of the CLO assets, there would no longer be any excess carrying value of CLO assets over the carrying value of CLO liabilities to be reported as “appropriated retained earnings — managed investment entities” in AFG’s Balance Sheet or any CLO earnings to be attributed to noncontrolling interests in AFG’s Statement of Earnings. If AFG elects to continue to measure both the CLO assets and liabilities at fair value, ASU 2014-13 will require amounts currently reflected as “appropriated retained earnings — managed investment entities” to be reclassified to unappropriated retained earnings in the Balance Sheet and amounts currently attributed to noncontrolling interests in the Statement of Earnings to be included in earnings attributable to AFG shareholders. Although ASU 2014-13 is not required to be adopted until 2016, AFG intends to early adopt the guidance effective January 1, 2015 (as permitted) and to elect the alternative measurement guidance on a modified retrospective basis. As a result, the amount reported as “appropriated retained earnings — managed investment entities” in AFG’s Balance Sheet at December 31, 2014 will effectively be reclassified to “liabilities of managed investment entities” on January 1, 2015. While the ASU will have an impact on the future presentation of individual CLO-related line items in AFG’s Statement of Earnings in future periods, it will have no overall impact on AFG’s net earnings attributable to shareholders.
	Unpaid Losses and Loss Adjustment Expenses   The net liabilities stated for unpaid claims and for expenses of investigation and adjustment of unpaid claims represent management’s best estimate and are based upon (i) the accumulation of case estimates for losses reported prior to the close of the accounting period on direct business written; (ii) estimates received from ceding reinsurers and insurance pools and associations; (iii) estimates of unreported losses (including possible development on known claims) based on past experience; (iv) estimates based on experience of expenses for investigating and adjusting claims; and (v) the current state of the law and coverage litigation. Establishing reserves for asbestos, environmental and other mass tort claims involves considerably more judgment than other types of claims due to, among other things, inconsistent court decisions, an increase in bankruptcy filings as a result of asbestos-related liabilities, novel theories of coverage, and judicial interpretations that often expand theories of recovery and broaden the scope of coverage.
	Loss reserve liabilities are subject to the impact of changes in claim amounts and frequency and other factors. Changes in estimates of the liabilities for losses and loss adjustment expenses are reflected in the Statement of Earnings in the period in which determined. Despite the variability inherent in such estimates, management believes that the liabilities for unpaid losses and loss adjustment expenses are adequate.
	Annuity Benefits Accumulated   Annuity receipts and benefit payments are recorded as increases or decreases in annuity benefits accumulated rather than as revenue and expense. Increases in this liability for interest credited are charged to expense and decreases for policy charges are credited to other income.
	For certain products, annuity benefits accumulated also includes reserves for accrued persistency and premium bonuses, guaranteed withdrawals and excess benefits expected to be paid on future deaths and annuitizations (“EDAR”). The liabilities for EDAR and guaranteed withdrawals are accrued for and modified using assumptions consistent with those used in determining DPAC and DPAC amortization, except that amounts are determined in relation to the present value of total expected assessments. Total expected assessments consist principally of estimated future investment margin, surrender, mortality, and other life and annuity policy charges, and unearned revenues once they are recognized as income.
	Annuity benefits accumulated also includes amounts advanced from the Federal Home Loan Bank of Cincinnati.
	Unearned Revenue   Certain upfront policy charges on annuities are deferred as unearned revenue (included in other liabilities) and recognized in net earnings using the same assumptions and estimated gross profits used to amortize DPAC.
	Life, Accident and Health Reserves   Liabilities for future policy benefits under traditional life, accident and health policies are computed using the net level premium method. Computations are based on the original projections of investment yields, mortality, morbidity and surrenders and include provisions for unfavorable deviations unless a loss recognition event (premium deficiency) occurs. Claim reserves and liabilities established for accident and health claims are modified as necessary to reflect actual experience and developing trends.
	For long-duration contracts (such as traditional life and long-term care policies), loss recognition occurs when, based on current expectations as of the measurement date, existing contract liabilities plus the present value of future premiums (including reasonably expected rate increases) are not expected to cover the present value of future claims payments and related settlement and maintenance costs (excluding overhead) as well as unamortized acquisition costs. If a block of business is determined to be in loss recognition, a charge is recorded in earnings in an amount equal to the excess of the present value of expected future claims costs and unamortized acquisition costs over existing reserves plus the present value of expected future premiums (with no provision for adverse deviation). The charge is recorded first to reduce unamortized acquisition costs and then as an additional reserve (if unamortized acquisition costs have been reduced to zero).
	In addition, reserves for traditional life and long-term care policies are subject to adjustment for loss recognition charges that would have been recorded if the unrealized gains from securities had actually been realized. This adjustment is included in unrealized gains (losses) on marketable securities, a component of AOCI in AFG’s Balance Sheet.
	Variable Annuity Assets and Liabilities   Separate accounts related to variable annuities represent the fair value of deposits invested in underlying investment funds on which AFG earns a fee. Investment funds are selected and may be changed only by the policyholder, who retains all investment risk.
	AFG’s variable annuity contracts contain a guaranteed minimum death benefit (“GMDB”) to be paid if the policyholder dies before the annuity payout period commences. In periods of declining equity markets, the GMDB may exceed the value of the policyholder’s account. A GMDB liability is established for future excess death benefits using assumptions together with a range of reasonably possible scenarios for investment fund performance that are consistent with DPAC capitalization and amortization assumptions.
	Premium Recognition   Property and casualty premiums are earned generally over the terms of the policies on a pro rata basis. Unearned premiums represent that portion of premiums written which is applicable to the unexpired terms of policies in force. On reinsurance assumed from other insurance companies or written through various underwriting organizations, unearned premiums are based on information received from such companies and organizations. For traditional life, accident and health products, premiums are recognized as revenue when legally collectible from policyholders. For interest-sensitive life and universal life products, premiums are recorded in a policyholder account, which is reflected as a liability. Revenue is recognized as amounts are assessed against the policyholder account for mortality coverage and contract expenses.
	Noncontrolling Interests   For Balance Sheet purposes, noncontrolling interests represents the interests of shareholders other than AFG in consolidated entities. In the Statement of Earnings, net earnings and losses attributable to noncontrolling interests represents such shareholders’ interest in the earnings and losses of those entities.
	Income Taxes   Deferred income taxes are calculated using the liability method. Under this method, deferred income tax assets and liabilities are determined based on differences between financial reporting and tax bases and are measured using enacted tax rates. A valuation allowance is established to reduce total deferred tax assets to an amount that will more likely than not be realized.
	AFG recognizes the tax benefits of uncertain tax positions only when the position is more likely than not to be sustained under examination by the appropriate taxing authority. Interest and penalties on AFG’s reserve for uncertain tax positions are recognized as a component of tax expense.
	Stock-Based Compensation   All share-based grants are recognized as compensation expense on a straight-line basis over their vesting periods based on their calculated fair value at the date of grant. AFG uses the Black-Scholes pricing model to measure the fair value of employee stock options. See Note K — “Shareholders’ Equity” for further information.
	Benefit Plans   AFG provides retirement benefits to qualified employees of participating companies through the AFG 401(k) Retirement and Savings Plan, a defined contribution plan. AFG makes all contributions to the retirement fund portion of the plan and matches a percentage of employee contributions to the savings fund. Company contributions are expensed in the year for which they are declared. AFG and many of its subsidiaries provide health care and life insurance benefits to eligible retirees. AFG also provides postemployment benefits to former or inactive employees (primarily those on disability) who were not deemed retired under other company plans. The projected future cost of providing these benefits is expensed over the period employees earn such benefits.
	Earnings Per Share   Although basic earnings per share only considers shares of common stock outstanding during the period, the calculation of diluted earnings per share includes the following adjustments to weighted average common shares related to stock-based compensation plans: 2014 – 2.0 million, 2013 – 1.9 million and 2012 – 1.7 million.
	AFG’s weighted average diluted shares outstanding excludes the following anti-dilutive potential common shares related to stock compensation plans: 2014 – 1.0 million, 2013 – 1.1 million and 2012 – 1.8 million. Adjustments to net earnings attributable to shareholders in the calculation of diluted earnings per share were nominal in the 2014, 2013 and 2012 periods.
	Statement of Cash Flows   For cash flow purposes, “investing activities” are defined as making and collecting loans and acquiring and disposing of debt or equity instruments and property and equipment. “Financing activities” include obtaining resources from owners and providing them with a return on their investments, borrowing money and repaying amounts borrowed. Annuity receipts, surrenders, benefits and withdrawals are also reflected as financing activities. All other activities are considered “operating.” Short-term investments having original maturities of three months or less when purchased are considered to be cash equivalents for purposes of the financial statements.

Acquisitions_and_Sales_of_Busi

Acquisitions and Sales of Businesses	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Acquisitions and Sales of Businesses	Acquisitions and Sales of Businesses
	Acquisition of Summit Holding Southeast, Inc.   On April 1, 2014, AFG acquired Summit Holding Southeast, Inc. and its related companies (“Summit”), from Liberty Mutual Insurance for $259 million using cash on hand at the parent company. Immediately following the acquisition, AFG made a capital contribution of $140 million, bringing its total capital investment in the Summit business to $399 million. Summit is based in Lakeland, Florida and is a leading provider of specialty workers’ compensation solutions in the southeastern United States with $539 million in net written premiums in 2014. Summit continues to operate under the Summit brand as a member of AFG’s Great American Insurance Group. Summit is included in the Specialty casualty sub-segment and generated $410 million in net earned premiums subsequent to AFG’s acquisition.
	Expenses related to the acquisition were less than $1 million and were expensed as incurred. The purchase price was allocated to the acquired assets and liabilities of Summit based on management’s best estimate of fair value as of the acquisition date. The allocation of the purchase price is shown in the table below (in millions):
	Total purchase price				$	259
	Tangible assets acquired:
	Cash and cash equivalents	$	1,078
	Fixed maturities, available for sale	92
	Recoverables from reinsurers	116
	Agents’ balances and premiums receivable	41
	Deferred tax assets, net (a)	67
	Other receivables	21
	Other assets	11
	Total tangible assets acquired				1,426
	Liabilities acquired:
	Unpaid losses and loss adjustment expenses	1,142
	Unearned premiums	3
	Payable to reinsurers	3
	Other liabilities	66
	Total liabilities acquired				1,214
	Net tangible assets acquired, at fair value				212
	Excess purchase price over net tangible assets acquired				$	47
	Allocation of excess purchase price:
	Intangible assets acquired (b)				$	47
	Deferred tax on intangible assets acquired (a)				(16		)
	Goodwill				16
					$	47
	(a)	Included with AFG’s net deferred tax liabilities, which are included in Other liabilities in AFG’s Consolidated Balance Sheet.
	(b)	Included in Other assets in AFG’s Consolidated Balance Sheet.
	AFG believes that the agents’ balances and other acquired receivables are collectible. The intangible assets acquired include $1 million in indefinite lived intangible assets related to state insurance licenses and $46 million in finite lived intangibles, primarily related to agency relationships. The finite lived intangibles are being amortized over an average expected life of 7 years. The fair value of the acquired liability for unpaid losses and loss adjustment expenses and related recoverables from reinsurers was estimated by discounting actuarial projected future net cash flows using the U.S. Treasury yield curve (with an adjustment for the illiquidity of insurance reserves) and then adding a risk adjustment to reflect the net present value of the profit that a market participant would require in return for the assumption of the risk associated with the reserves. The fair value of Summit’s agency relationship was estimated using a multi-period excess earnings method, which is a form of the income approach. The acquisition resulted in the recognition of $16 million in non-deductible goodwill based on the excess of the purchase price over the fair value of the net assets acquired. The goodwill represents the fair value of acquired intangible assets that do not qualify for separate recognition, including the value of Summit’s assembled workforce.
	Sale of Medicare Supplement and Critical Illness Segment   In August 2012, AFG completed the sale of its Medicare supplement and critical illness businesses, which included Loyal American Life Insurance Company and four other insurance companies, to Cigna Corporation for $326 million in cash resulting in a pretax gain of $170 million (including post-closing adjustments). Since the transaction includes the ongoing cessions of certain business to Cigna, the operations being sold are not reported as discontinued operations.
	The impact of the August 2012 sale of the Medicare supplement and critical illness segment on AFG’s financial statements is shown below (in millions):
		2012
	Sale proceeds	$	326
	Expenses	(11		)
	Net proceeds	$	315
	Assets of businesses sold:
	Cash and investments	$	217
	Deferred policy acquisition costs	108
	Other assets	31
	Total assets	356
	Liabilities of businesses sold:
	Life, accident and health reserves	209
	Other liabilities	2
	Total liabilities	211
	Net assets of businesses sold	$	145
	Gain on sale of subsidiaries	$	170
	Total 2012 revenues, costs and expenses, and earnings before income taxes for the Medicare supplement and critical illness segment through the sale date were $212 million, $184 million and $28 million, respectively.
	Acquisitions and Sale of Other Businesses   On March 27, 2014, AFG completed a renewal rights agreement with Selective Insurance Company of America to acquire Selective’s pooled public entity book of business for $8 million. At the acquisition date, this book of business had approximately $38 million in in-force gross written premiums.
	During 2012, AFG acquired the outstanding 28% of Marketform, its London-based Lloyd’s property and casualty insurance operation, that it did not already own for $17 million and sold a small annuity company for $7 million.

Segments_of_Operations

Segments of Operations	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segments of Operations	Segments of Operations
	AFG manages its business as five segments: (i) Property and casualty insurance, (ii) Annuity, (iii) Run-off long-term care and life, (iv) Medicare supplement and critical illness (sold in August 2012) and (v) Other, which includes holding company assets and costs, and the assets and operations attributable to the noncontrolling interests of the managed investment entities.
	AFG reports its property and casualty insurance business in the following Specialty sub-segments: (i) Property and transportation, which includes physical damage and liability coverage for buses, trucks and recreational vehicles, inland and ocean marine, agricultural-related products and other property coverages, (ii) Specialty casualty, which includes primarily excess and surplus, general liability, executive liability, professional liability, umbrella and excess liability, specialty coverage in targeted markets, customized programs for small to mid-sized businesses and workers’ compensation insurance, and (iii) Specialty financial, which includes risk management insurance programs for leasing and financing institutions (including collateral and lender-placed mortgage property insurance), surety and fidelity products and trade credit insurance. Premiums and underwriting profit included under Other specialty represent business assumed by AFG’s internal reinsurance program from the operations that make up AFG’s other Specialty sub-segments and amortization of deferred gains on retroactive reinsurance transactions related to the sales of businesses in prior years. AFG’s annuity business markets traditional fixed and fixed-indexed annuities in the retail, financial institutions and education markets. AFG’s reportable segments and their components were determined based primarily upon similar economic characteristics, products and services.
	Sales of property and casualty insurance outside of the United States represented 5% of AFG’s revenues in 2014, 2013 and 2012.
	The following tables (in millions) show AFG’s assets, revenues and earnings before income taxes by segment and sub-segment.
		2014			2013			2012
	Assets
	Property and casualty insurance (a)	$	14,069		$	11,717		$	12,163
	Annuity	27,317			24,294			20,909
	Run-off long-term care and life	2,489			2,408			2,304
	Other	3,660			3,668			3,795
	Total assets	$	47,535		$	42,087		$	39,171
	Revenues
	Property and casualty insurance:
	Premiums earned:
	Specialty
	Property and transportation	$	1,544		$	1,521		$	1,423
	Specialty casualty	1,765			1,135			948
	Specialty financial	469			469			405
	Other specialty	100			79			71
	Total premiums earned	3,878			3,204			2,847
	Net investment income	294			263			275
	Other income	9			15			24
	Total property and casualty insurance	4,181			3,482			3,146
	Annuity:
	Net investment income	1,136			1,034			976
	Other income	78			67			52
	Total annuity	1,214			1,101			1,028
	Run-off long-term care and life	194			194			191
	Medicare supplement and critical illness (b)	—			—			212
	Other	72			98			9
	Total revenues before realized gains (losses)	5,661			4,875			4,586
	Realized gains on securities	52			221			210
	Realized gains (losses) on subsidiaries	—			(4		)	161
	Total revenues	$	5,713		$	5,092		$	4,957
	(a)   Not allocable to sub-segments.
	(b)   Sold in August 2012.
		2014			2013			2012
	Earnings Before Income Taxes
	Property and casualty insurance:
	Underwriting:
	Specialty
	Property and transportation	$	21		$	12		$	19
	Specialty casualty	136			102			53
	Specialty financial	64			67			44
	Other specialty	16			25			15
	Other lines (a)	(25		)	(61		)	(44		)
	Total underwriting	212			145			87
	Investment and other income, net	244			230			235
	Total property and casualty insurance	456			375			322
	Annuity (b)	328			323			256
	Run-off long-term care and life (c)	(10		)	(10		)	(157		)
	Medicare supplement and critical illness (d)	—			—			28
	Other (e)	(200		)	(216		)	(283		)
	Total earnings before realized gains (losses) and income taxes	574			472			166
	Realized gains on securities	52			221			210
	Realized gains (losses) on subsidiaries	—			(4		)	161
	Total earnings before income taxes	$	626		$	689		$	537
	(a)	Includes special charges to increase asbestos and environmental (“A&E”) reserves of $24 million, $54 million and $31 million in 2014, 2013 and 2012, respectively.
	(b)	Includes a $5 million charge in the second quarter of 2013 to cover expected assessments from state guaranty funds related to insolvency and liquidation of an unaffiliated life insurance company.
	(c)	Includes a loss recognition charge of $153 million in the fourth quarter of 2012.
	(d)	Sold in August 2012.
	(e)	Includes holding company expenses, special charges to increase A&E reserves ($6 million in 2014, $22 million in 2013 and $2 million in 2012) and losses of managed investment entities attributable to noncontrolling interests ($51 million in 2014, $26 million in 2013 and $98 million in 2012). Holding company expenses in 2012 also include an $8 million loss on retirement of debt and a $15 million charge for a labor matter related to AFG’s former railroad operations.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements
	Accounting standards for measuring fair value are based on inputs used in estimating fair value. The three levels of the hierarchy are as follows:
	Level 1 — Quoted prices for identical assets or liabilities in active markets (markets in which transactions occur with sufficient frequency and volume to provide pricing information on an ongoing basis). AFG’s Level 1 financial instruments consist primarily of publicly traded equity securities and highly liquid government bonds for which quoted market prices in active markets are available and short-term investments of managed investment entities.
	Level 2 — Quoted prices for similar instruments in active markets; quoted prices for identical or similar assets or liabilities in inactive markets (markets in which there are few transactions, the prices are not current, price quotations vary substantially over time or among market makers, or in which little information is released publicly); and valuations based on other significant inputs that are observable in active markets. AFG’s Level 2 financial instruments include separate account assets, corporate and municipal fixed maturity securities, mortgage-backed securities (“MBS”) and investments of managed investment entities priced using observable inputs. Level 2 inputs include benchmark yields, reported trades, corroborated broker/dealer quotes, issuer spreads and benchmark securities. When non-binding broker quotes can be corroborated by comparison to similar securities priced using observable inputs, they are classified as Level 2.
	Level 3 — Valuations derived from market valuation techniques generally consistent with those used to estimate the fair values of Level 2 financial instruments in which one or more significant inputs are unobservable or when the market for a security exhibits significantly less liquidity relative to markets supporting Level 2 fair value measurements. The unobservable inputs may include management’s own assumptions about the assumptions market participants would use based on the best information available in the circumstances. AFG’s Level 3 is comprised of financial instruments, including liabilities of managed investment entities, whose fair value is estimated based on non-binding broker quotes or internally developed using significant inputs not based on, or corroborated by, observable market information.
	AFG’s management is responsible for the valuation process and uses data from outside sources (including nationally recognized pricing services and broker/dealers) in establishing fair value. AFG’s internal investment professionals are a group of approximately 20 analysts whose primary responsibility is to manage AFG’s investment portfolio. These professionals monitor individual investments as well as overall industries and are active in the financial markets on a daily basis. The group is led by AFG’s chief investment officer, who reports directly to one of AFG’s Co-CEOs. Valuation techniques utilized by pricing services and prices obtained from external sources are reviewed by AFG’s internal investment professionals who are familiar with the securities being priced and the markets in which they trade to ensure the fair value determination is representative of an exit price. To validate the appropriateness of the prices obtained, these investment managers consider widely published indices (as benchmarks), recent trades, changes in interest rates, general economic conditions and the credit quality of the specific issuers. In addition, the Company communicates directly with the pricing service regarding the methods and assumptions used in pricing, including verifying, on a test basis, the inputs used by the service to value specific securities.
	Assets and liabilities measured and carried at fair value in the financial statements are summarized below (in millions):
		Level 1				Level 2			Level 3			Total
	31-Dec-14
	Assets:
	Available for sale (“AFS”) fixed maturities:
	U.S. Government and government agencies	$	164			$	174		$	15		$	353
	States, municipalities and political subdivisions	—				6,647			100			6,747
	Foreign government	—				194			—			194
	Residential MBS	—				4,142			300			4,442
	Commercial MBS	—				2,407			44			2,451
	Asset-backed securities (“ABS”)	—				3,661			226			3,887
	Corporate and other	36				12,078			546			12,660
	Total AFS fixed maturities	200				29,303			1,231			30,734
	Trading fixed maturities	12				254			—			266
	Equity securities	1,306				297			93			1,696
	Assets of managed investment entities (“MIE”)	174				2,903			31			3,108
	Variable annuity assets (separate accounts) (*)	—				662			—			662
	Other investments — derivatives	—				322			—			322
	Total assets accounted for at fair value	$	1,692			$	33,741		$	1,355		$	36,788
	Liabilities:
	Liabilities of managed investment entities	$	118			$	—		$	2,701		$	2,819
	Derivatives in annuity benefits accumulated	—				—			1,160			1,160
	Other liabilities — derivatives	—				13			—			13
	Total liabilities accounted for at fair value	$	118			$	13		$	3,861		$	3,992
	31-Dec-13
	Assets:
	Available for sale fixed maturities:
	U.S. Government and government agencies	$	147			$	152		$	15		$	314
	States, municipalities and political subdivisions	—				5,311			61			5,372
	Foreign government	—				208			—			208
	Residential MBS	—				3,994			316			4,310
	Commercial MBS	—				2,696			28			2,724
	Asset-backed securities	—				2,418			75			2,493
	Corporate and other	28				10,672			335			11,035
	Total AFS fixed maturities	175				25,451			830			26,456
	Trading fixed maturities	—				305			—			305
	Equity securities	1,023				125			31			1,179
	Assets of managed investment entities	266				2,592			30			2,888
	Variable annuity assets (separate accounts) (*)	—				665			—			665
	Other investments — derivatives	—				274			—			274
	Total assets accounted for at fair value	$	1,464			$	29,412		$	891		$	31,767
	Liabilities:
	Liabilities of managed investment entities	$	156			$	—		$	2,411		$	2,567
	Derivatives in annuity benefits accumulated	—				—			804			804
	Other liabilities — derivatives	—				10			—			10
	Total liabilities accounted for at fair value	$	156			$	10		$	3,215		$	3,381
	(*)   Variable annuity liabilities equal the fair value of variable annuity assets.
	The transfers between Level 1 and Level 2 for the years ended December 31, 2014, 2013 and 2012 are reflected in the table below at fair value as of the end of the reporting period (dollars in millions):
		Level 2 To Level 1 Transfers																	Level 1 To Level 2 Transfers
		# of Transfers								Fair Value									# of Transfers							Fair Value
		2014			2013			2012		2014			2013			2012			2014	2013			2012			2014		2013		2012
	Perpetual preferred stocks	14			15			2		$	96		$	70		$	16		13	2			7			$	83	$	10	$	41
	Common stocks	—			2			—		—			35			—			7	—			—			26		—		—
	Redeemable preferred stocks	1			3			1		5			21			2			—	—			—			—		—		—
	The transfers from Level 2 to Level 1 are due to increases in trade frequency, resulting in trade data sufficient to warrant classification in Level 1. The transfers from Level 1 to Level 2 are due to decreases in trade frequency, resulting in lack of available trade data sufficient to warrant classification in Level 1. Approximately 3.5% of the total assets carried at fair value on December 31, 2014, were Level 3 assets. Approximately 79% ($1.07 billion) of the Level 3 assets were priced using non-binding broker quotes, for which there is a lack of transparency as to the inputs used to determine fair value. Details as to the quantitative inputs are neither provided by the brokers nor otherwise reasonably obtainable by AFG. Since internally developed Level 3 asset fair values represent less than 1% of the total assets measured at fair value and less than 5% of AFG’s shareholders’ equity, changes in unobservable inputs used to determine internally developed fair values would not have a material impact on AFG’s financial position.
	The fair values of the liabilities of managed investment entities were determined using primarily non-binding broker quotes, which were reviewed by AFG’s investment professionals. AFG’s investment professionals are familiar with the cash flow models used by the brokers to determine the fair value of these liabilities and review the broker quotes based on their knowledge of the CLO market and the market for the underlying assets. Their review includes consideration of expected reinvestment, default and recovery rates on the assets supporting the CLO liabilities, as well as surveying general CLO liability fair values and analysis provided by third parties.
	The only significant Level 3 assets or liabilities carried at fair value in the financial statements that were not measured using broker quotes are the derivatives embedded in AFG’s fixed-indexed annuity liabilities, which are measured using a discounted cash flow approach and had a fair value of $1.16 billion at December 31, 2014. The following table presents information about the unobservable inputs used by management in determining fair value of these embedded derivatives. See Note F — “Derivatives.”
	Unobservable Input		Range
Adjustment for insurance subsidiary’s credit risk		0.40% – 1.75% over the risk free rate
Risk margin for uncertainty in cash flows		0.52% reduction in the discount rate
Surrenders		4% – 16% of indexed account value
Partial surrenders		2% – 6% of indexed account value
Annuitizations		1% – 1.5% of indexed account value
Deaths		1.5% – 3.0% of indexed account value
Budgeted option costs		2.25% – 3.5% of indexed account value
The range of adjustments for insurance subsidiary’s credit risk reflects credit spread variations across the yield curve. The range of projected surrender rates reflects the specific surrender charges and other features of AFG’s individual fixed-indexed annuity products with an expected range of 5% to 11% in the majority of future calendar years (4% to 16% over all periods). Increasing the budgeted option cost or risk margin for uncertainty in cash flows assumptions in the table above would increase the fair value of the fixed-indexed annuity embedded derivatives, while increasing any of the other unobservable inputs in the table above would decrease the fair value of the embedded derivatives.
Changes in balances of Level 3 financial assets and liabilities carried at fair value during 2014, 2013 and 2012 are presented below (in millions). The transfers into and out of Level 3 were due to changes in the availability of market observable inputs. All transfers are reflected in the table at fair value as of the end of the reporting period.
					Total realized/unrealized
					gains (losses) included in
	Balance at December 31, 2013				Net			Other			Purchases			Sales and			Transfer		Transfer				Balance at December 31, 2014
					income			comprehensive			and			settlements			into		out of
								income (loss)			issuances						Level 3		Level 3
AFS fixed maturities:
U.S. government agency	$	15			$	—		$	—		$	—		$	—		$	—	$	—			$	15
State and municipal	61				(1		)	—			30			—			10		—				100
Residential MBS	316				4			3			13			(31		)	111		(116		)		300
Commercial MBS	28				(1		)	—			—			—			17		—				44
Asset-backed securities	75				3			(2		)	99			(39		)	117		(27		)		226
Corporate and other	335				2			13			102			(73		)	172		(5		)		546
Equity securities	31				1			2			62			(9		)	22		(16		)		93
Assets of MIE	30				(3		)	—			6			(2		)	—		—				31
Liabilities of MIE (a)	(2,411		)		22			—			(817		)	505			—		—				(2,701		)
Embedded derivatives (b)	(804		)		(182		)	—			(221		)	47			—		—				(1,160		)
(a)	Total realized/unrealized gains (losses) included in net income includes gains of $50 million related to liabilities outstanding as of December 31, 2014. See Note H — “Managed Investment Entities.”
(b)	Total realized/unrealized gains (losses) included in net income for the embedded derivatives reflects gains related to the unlocking of actuarial assumptions of $58 million in 2014.
					Total realized/unrealized
					gains (losses) included in
	Balance at December 31, 2012				Net			Other			Purchases			Sales and			Transfer		Transfer				Balance at December 31, 2013
					income			comprehensive			and			settlements			into		out of
								income (loss)			issuances						Level 3		Level 3
AFS fixed maturities:
U.S. government agency	$	20			$	(2	)	$	(3	)	$	—		$	—		$	—	$	—			$	15
State and municipal	58				(1		)	(2		)	10			—			—		(4		)		61
Residential MBS	371				5			24			6			(53		)	86		(123		)		316
Commercial MBS	22				(1		)	(1		)	—			—			8		—				28
Asset-backed securities	253				4			(3		)	12			(57		)	11		(145		)		75
Corporate and other	236				1			(14		)	113			(17		)	24		(8		)		335
Equity securities	37				(1		)	6			53			(12		)	—		(52		)		31
Assets of MIE	40				(5		)	—			8			(7		)	—		(6		)		30
Liabilities of MIE (a)	(2,745		)		(25		)	—			(728		)	1,068			—		19				(2,411		)
Embedded derivatives (b)	(465		)		(182		)	—			(192		)	35			—		—				(804		)
(a)	Total realized/unrealized gains (losses) included in net income includes gains of $7 million related to liabilities outstanding as of December 31, 2013. See Note H — “Managed Investment Entities.”
(b)	Total realized/unrealized gains (losses) included in net income for the embedded derivatives reflects gains related to the unlocking of actuarial assumptions of $2 million in 2013.
					Total realized/unrealized
					gains (losses) included in
	Balance at December 31, 2011				Net			Other			Purchases			Sales and			Transfer		Transfer				Balance at December 31, 2012
					income			comprehensive			and			settlements			into		out of
								income (loss)			issuances						Level 3		Level 3
AFS fixed maturities:
U.S. government agency	$	—			$	—		$	—		$	20		$	—		$	—	$	—			$	20
State and municipal	83				—			4			19			(7		)	8		(49		)		58
Residential MBS	361				5			17			96			(45		)	228		(291		)		371
Commercial MBS	19				1			2			—			—			—		—				22
Asset-backed securities	228				7			8			55			(36		)	14		(23		)		253
Corporate and other	291				3			9			86			(35		)	15		(133		)		236
Trading fixed maturities	1				—			—			—			—			—		(1		)		—
Equity securities	11				—			2			30			—			13		(19		)		37
Assets of MIE	44				—			—			20			(14		)	13		(23		)		40
Liabilities of MIE (a)	(2,593		)		(189		)	—			(793		)	830			—		—				(2,745		)
Embedded derivatives (b)	(361		)		(57		)	—			(73		)	26			—		—				(465		)
(a)	Total realized/unrealized gains (losses) included in net income includes losses of $125 million related to liabilities outstanding as of December 31, 2012. See Note H — “Managed Investment Entities.”
(b)	Total realized/unrealized gains (losses) included in net income for the embedded derivatives reflects gains related to the unlocking of actuarial assumptions of $36 million in 2012.
Fair Value of Financial Instruments   The carrying value and fair value of financial instruments that are not carried at fair value in the financial statements at December 31 are summarized below (in millions):
	Carrying				Fair			Level 1			Level 2			Level 3
	Value				Value
2014
Financial assets:
Cash and cash equivalents	$	1,343			$	1,343		$	1,343		$	—		$	—
Mortgage loans	1,117				1,124			—			—			1,124
Policy loans	228				228			—			—			228
Total financial assets not accounted for at fair value	$	2,688			$	2,695		$	1,343		$	—		$	1,352
Financial liabilities:
Annuity benefits accumulated (*)	$	23,561			$	23,187		$	—		$	—		$	23,187
Long-term debt	1,061				1,180			—			1,106			74
Total financial liabilities not accounted for at fair value	$	24,622			$	24,367		$	—		$	1,106		$	23,261
2013
Financial assets:
Cash and cash equivalents	$	1,639			$	1,639		$	1,639		$	—		$	—
Mortgage loans	781				779			—			—			779
Policy loans	238				238			—			—			238
Total financial assets not accounted for at fair value	$	2,658			$	2,656		$	1,639		$	—		$	1,017
Financial liabilities:
Annuity benefits accumulated (*)	$	20,741			$	19,959		$	—		$	—		$	19,959
Long-term debt	913				985			—			909			76
Total financial liabilities not accounted for at fair value	$	21,654			$	20,944		$	—		$	909		$	20,035
(*)	Excludes life contingent annuities in the payout phase.
The carrying amount of cash and cash equivalents approximates fair value. Fair values for mortgage loans are estimated by discounting the future contractual cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings. The fair value of policy loans is estimated to approximate carrying value; policy loans have no defined maturity dates and are inseparable from insurance contracts. The fair value of annuity benefits was estimated based on expected cash flows discounted using forward interest rates adjusted for the Company’s credit risk and includes the impact of maintenance expenses and capital costs. Fair values of long-term debt are based primarily on quoted market prices.

Investments

Investments	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Investments	Investments
	Available for sale fixed maturities and equity securities at December 31 consisted of the following (in millions):
		2014													2013
		Amortized				Fair			Gross Unrealized						Amortized			Fair			Gross Unrealized
		Cost				Value			Gains			Losses			Cost			Value			Gains			Losses
	Fixed maturities:
	U.S. Government and government agencies	$	347			$	353		$	8		$	(2	)	$	310		$	314		$	7		$	(3	)
	States, municipalities and political subdivisions	6,393				6,747			364			(10		)	5,360			5,372			156			(144		)
	Foreign government	184				194			10			—			198			208			10			—
	Residential MBS	4,046				4,442			411			(15		)	3,947			4,310			391			(28		)
	Commercial MBS	2,294				2,451			158			(1		)	2,535			2,724			192			(3		)
	Asset-backed securities	3,872				3,887			37			(22		)	2,477			2,493			35			(19		)
	Corporate and other	11,938				12,660			751			(29		)	10,539			11,035			604			(108		)
	Total fixed maturities	$	29,074			$	30,734		$	1,739		$	(79	)	$	25,366		$	26,456		$	1,395		$	(305	)
	Common stocks	$	885			$	1,087		$	227		$	(25	)	$	665		$	858		$	209		$	(16	)
	Perpetual preferred stocks	$	398			$	414		$	21		$	(5	)	$	266		$	265		$	9		$	(10	)
	The non-credit related portion of other-than-temporary impairment charges is included in other comprehensive income. Cumulative non-credit charges taken for securities still owned at December 31, 2014 and December 31, 2013, respectively, were $220 million and $229 million. Gross unrealized gains on such securities at December 31, 2014 and December 31, 2013 were $151 million and $150 million, respectively. Gross unrealized losses on such securities at December 31, 2014 and December 31, 2013 were $8 million and $13 million, respectively. These amounts represent the non-credit other-than-temporary impairment charges recorded in AOCI adjusted for subsequent changes in fair values and nearly all relate to residential MBS.
	The following tables show gross unrealized losses (dollars in millions) on fixed maturities and equity securities by investment category and length of time that individual securities have been in a continuous unrealized loss position at December 31, 2014 and 2013.
			Less Than Twelve Months									Twelve Months or More
			Unrealized				Fair			Fair Value as		Unrealized			Fair			Fair Value as
			Loss				Value			% of Cost		Loss			Value			% of Cost
		2014
		Fixed maturities:
		U.S. Government and government agencies	$	—			$	39		100	%	$	(2	)	$	15		88	%
		States, municipalities and political subdivisions	(2		)		222			99	%	(8		)	408			98	%
		Residential MBS	(4		)		298			99	%	(11		)	209			95	%
		Commercial MBS	(1		)		38			97	%	—			11			100	%
		Asset-backed securities	(11		)		1,389			99	%	(11		)	622			98	%
		Corporate and other	(16		)		588			97	%	(13		)	433			97	%
		Total fixed maturities	$	(34	)		$	2,574		99	%	$	(45	)	$	1,698		97	%
		Common stocks	$	(25	)		$	260		91	%	$	—		$	—		—	%
		Perpetual preferred stocks	$	(1	)		$	45		98	%	$	(4	)	$	55		93	%
		2013
		Fixed maturities:
		U.S. Government and government agencies	$	(3	)		$	60		95	%	$	—		$	—		—	%
		States, municipalities and political subdivisions	(135		)		2,219			94	%	(9		)	73			89	%
		Residential MBS	(9		)		553			98	%	(19		)	212			92	%
		Commercial MBS	(3		)		106			97	%	—			2			100	%
		Asset-backed securities	(18		)		1,310			99	%	(1		)	28			97	%
		Corporate and other	(101		)		2,634			96	%	(7		)	85			92	%
		Total fixed maturities	$	(269	)		$	6,882		96	%	$	(36	)	$	400		92	%
		Common stocks	$	(16	)		$	158		91	%	$	—		$	—		—	%
		Perpetual preferred stocks	$	(6	)		$	91		94	%	$	(4	)	$	20		83	%
	At December 31, 2014, the gross unrealized losses on fixed maturities of $79 million relate to approximately 650 securities. Investment grade securities (as determined by nationally recognized rating agencies) represented approximately 70% of the gross unrealized loss and 85% of the fair value.
	The determination of whether unrealized losses are “other-than-temporary” requires judgment based on subjective as well as objective factors. Factors considered and resources used by management include:
	a)	whether the unrealized loss is credit-driven or a result of changes in market interest rates,
	b)	the extent to which fair value is less than cost basis,
	c)	cash flow projections received from independent sources,
	d)	historical operating, balance sheet and cash flow data contained in issuer SEC filings and news releases,
	e)	near-term prospects for improvement in the issuer and/or its industry,
	f)	third party research and communications with industry specialists,
	g)	financial models and forecasts,
	h)	the continuity of dividend payments, maintenance of investment grade ratings and hybrid nature of certain investments,
	i)	discussions with issuer management, and
	j)	ability and intent to hold the investment for a period of time sufficient to allow for anticipated recovery in fair value.
	AFG analyzes its MBS securities for other-than-temporary impairment each quarter based upon expected future cash flows. Management estimates expected future cash flows based upon its knowledge of the MBS market, cash flow projections (which reflect loan to collateral values, subordination, vintage and geographic concentration) received from independent sources, implied cash flows inherent in security ratings and analysis of historical payment data. For 2014, AFG recorded less than $1 million in other-than-temporary impairment charges related to its residential MBS.
	AFG recorded $26 million in other-than-temporary impairment charges on common stocks in 2014. At December 31, 2014, the gross unrealized losses on common stocks of $25 million relate to 34 securities, none of which has been in an unrealized loss position for more than 12 months.
	AFG recorded less than $1 million in other-than-temporary charges on preferred stocks during 2014. At December 31, 2014, the gross unrealized losses on preferred stocks of $5 million relate to 19 securities. All of the preferred stocks that have been in an unrealized loss position for 12 months or more (8 securities) have investment grade ratings.
	Management believes AFG will recover its cost basis in the securities with unrealized losses and that AFG has the ability to hold the securities until they recover in value and had no intent to sell them at December 31, 2014.
	A progression of the credit portion of other-than-temporary impairments on fixed maturity securities for which the non-credit portion of an impairment has been recognized in other comprehensive income is shown below (in millions):
		2014				2013			2012
	Balance at January 1	$	194			$	192		$	187
	Additional credit impairments on:
	Previously impaired securities	—				—			5
Securities without prior impairments	—				3			2
Reductions due to sales or redemptions	(24		)		(1		)	(2		)
Balance at December 31	$	170			$	194		$	192
The table below sets forth the scheduled maturities of available for sale fixed maturities as of December 31, 2014 (dollars in millions). Securities with sinking funds are reported at average maturity. Actual maturities may differ from contractual maturities because certain securities may be called or prepaid by the issuers.
	Amortized				Fair Value
	Cost				Amount			%
Maturity
One year or less	$	888			$	906		3	%
After one year through five years	4,803				5,142			17	%
After five years through ten years	8,797				9,211			30	%
After ten years	4,374				4,695			15	%
	18,862				19,954			65	%
ABS (average life of approximately 4-1/2 years)	3,872				3,887			13	%
MBS (average life of approximately 4-1/2 years)	6,340				6,893			22	%
Total	$	29,074			$	30,734		100	%
Certain risks are inherent in connection with fixed maturity securities, including loss upon default, price volatility in reaction to changes in interest rates, and general market factors and risks associated with reinvestment of proceeds due to prepayments or redemptions in a period of declining interest rates.
There were no investments in individual issuers that exceeded 10% of Shareholders’ Equity at December 31, 2014 or 2013.
Net Unrealized Gain on Marketable Securities   In addition to adjusting equity securities and fixed maturity securities classified as “available for sale” to fair value, GAAP requires that deferred policy acquisition costs and certain other balance sheet amounts related to annuity, long-term care and life businesses be adjusted to the extent that unrealized gains and losses from securities would result in adjustments to those balances had the unrealized gains or losses actually been realized. The following table shows (in millions) the components of the net unrealized gain on securities that is included in AOCI in AFG’s Balance Sheet.
	Pretax				Deferred Tax and			Net
					Amounts  Attributable
					to Noncontrolling
					Interests
31-Dec-14
Unrealized gain on:
Fixed maturities — annuity segment (*)	$	1,157			$	(405	)	$	752
Fixed maturities — all other	503				(185		)	318
Equity securities	218				(79		)	139
Deferred policy acquisition costs — annuity segment	(531		)		186			(345		)
Annuity benefits accumulated	(112		)		39			(73		)
Life, accident and health reserves	(104		)		36			(68		)
Unearned revenue	31				(11		)	20
	$	1,162			$	(419	)	$	743
31-Dec-13
Unrealized gain on:
Fixed maturities — annuity segment (*)	$	729			$	(255	)	$	474
Fixed maturities — all other	361				(133		)	228
Equity securities	192				(70		)	122
Deferred policy acquisition costs — annuity segment	(345		)		121			(224		)
Annuity benefits accumulated	(71		)		25			(46		)
Life, accident and health reserves	(8		)		3			(5		)
Unearned revenue	22				(8		)	14
	$	880			$	(317	)	$	563
(*)    Unrealized gains on fixed maturity investments supporting AFG’s annuity benefits accumulated.
Net Investment Income   The following table shows (in millions) investment income earned and investment expenses incurred.
	2014				2013			2012
Investment income:
Fixed maturities	$	1,352			$	1,241		$	1,216
Equity securities	66				50			36
Equity in earnings of partnerships and similar investments (*)	18				—			—
Other	77				72			66
Gross investment income	1,513				1,363			1,318
Investment expenses	(12		)		(17		)	(17		)
Net investment income	$	1,501			$	1,346		$	1,301
(*)	Equity in the earnings of partnerships has not been material and was included in realized gains (losses) on securities prior to 2014.
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments are summarized as follows (in millions):
	Fixed				Equity			Mortgage			Other (a)			Tax			Noncon-			Total
	Maturities				Securities			Loans						Effects			trolling
								and Other									Interests
								Investments
Year ended December 31, 2014
Realized before impairments	$	36			$	53		$	1		$	(2	)	$	(32	)	$	(2	)	$	54
Realized — impairments	(15		)		(26		)	—			5			13			1			(22		)
Change in unrealized	570				26			—			(314		)	(99		)	(3		)	180
Year ended December 31, 2013
Realized before impairments	$	36			$	196		$	2		$	(1	)	$	(82	)	$	(2	)	$	149
Realized — impairments	(5		)		(5		)	(5		)	3			4			—			(8		)
Change in unrealized	(945		)		31			—			504			144			6			(260		)
Year ended December 31, 2012
Realized before impairments	$	55			$	192		$	(3	)	$	(8	)	$	(83	)	$	(2	)	$	151
Realized — impairments	(9		)		(24		)	—			7			9			—			(17		)
Change in unrealized	790				(23		)	—			(379		)	(136		)	(7		)	245
(a)	Primarily adjustments to deferred policy acquisition costs and reserves related to annuities and long-term care business.
Gross realized gains and losses (excluding impairment writedowns and mark-to-market of derivatives) on available for sale fixed maturity and equity security investment transactions included in the Statement of Cash Flows consisted of the following (in millions):
	2014				2013			2012
Fixed maturities:
Gross gains	$	36			$	44		$	55
Gross losses	(2		)		(5		)	(4		)
Equity securities:
Gross gains	53				193			196
Gross losses	—				—			(4		)

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives
	As discussed under “Derivatives” in Note A — “Accounting Policies” to the financial statements, AFG uses derivatives in certain areas of its operations.
	Derivatives That Do Not Qualify for Hedge Accounting   The following derivatives that do not qualify for hedge accounting under GAAP are included in AFG’s Balance Sheet at fair value (in millions):
				31-Dec-14						31-Dec-13
	Derivative		Balance Sheet Line	Asset			Liability			Asset			Liability
	MBS with embedded derivatives		Fixed maturities	$	158		$	—		$	140		$	—
	Public company warrants		Equity securities	19			—			19			—
	Interest rate swaptions		Other investments	—			—			2			—
	Fixed-indexed annuities (embedded derivative)		Annuity benefits accumulated	—			1,160			—			804
	Equity index call options		Other investments	322			—			272			—
	Reinsurance contracts (embedded derivative)		Other liabilities	—			13			—			10
				$	499		$	1,173		$	433		$	814
	The MBS with embedded derivatives consist primarily of interest-only MBS with interest rates that float inversely with short-term rates. AFG records the entire change in the fair value of these securities in earnings. These investments are part of AFG’s overall investment strategy and represent a small component of AFG’s overall investment portfolio.
	Warrants to purchase shares of publicly traded companies, which represent a small component of AFG’s overall investment portfolio, are considered to be derivatives that must be marked to market through earnings.
	AFG has $200 million notional amount of pay-fixed interest rate swaptions (options to enter into pay-fixed/receive floating interest rate swaps at future dates expiring in 2015) outstanding at December 31, 2014, which are used to mitigate interest rate risk in its annuity operations. AFG paid $4 million to purchase these swaptions, which represents its maximum potential economic loss over the life of the contracts.
	AFG’s fixed-indexed annuities, which represented approximately one-half of annuity benefits accumulated at December 31, 2014, provide policyholders with a crediting rate tied, in part, to the performance of an existing stock market index. AFG attempts to mitigate the risk in the index-based component of these products through the purchase of call options on the appropriate index. AFG receives collateral from its counterparties to support its purchased call option assets. This collateral ($285 million at December 31, 2014) is included in other assets in AFG’s Balance Sheet with an offsetting liability to return the collateral, which is included in other liabilities. AFG’s strategy is designed so that an increase in the liabilities, due to an increase in the market index, will be generally offset by unrealized and realized gains on the call options purchased by AFG. Both the index-based component of the annuities and the related call options are considered derivatives. Fluctuations in interest rates and the stock market, among other factors, can cause volatility in the periodic measurement of fair value of the embedded derivative that management believes can be inconsistent with the long-term economics of these products.
	As discussed under “Reinsurance” in Note A to the financial statements, certain reinsurance contracts are considered to contain embedded derivatives.
	The following table summarizes the gain (loss) included in the Statement of Earnings for changes in the fair value of derivatives that do not qualify for hedge accounting for 2014, 2013 and 2012 (in millions):
	Derivative		Statement of Earnings Line	2014			2013			2012
	MBS with embedded derivatives		Realized gains on securities	$	3		$	(3	)	$	5
	Public company warrants		Realized gains on securities	—			3			—
	Interest rate swaptions		Realized gains on securities	(2		)	1			(4		)
	Fixed-indexed annuities (embedded derivative) (*)		Annuity benefits	(182		)	(182		)	(57		)
	Equity index call options		Annuity benefits	181			210			66
	Reinsurance contracts (embedded derivative)		Net investment income	(3		)	7			(6		)
				$	(3	)	$	36		$	4
	(*)	The change in fair value of the embedded derivative includes gains related to unlocking of actuarial assumptions of $58 million in 2014, $2 million in 2013 and $36 million in 2012.
	Derivatives Designated and Qualifying as Cash Flow Hedges   In the third quarter of 2014, AFG entered into a five-year $431 million notional amount interest rate swap under which AFG receives fixed rate interest payments in exchange for variable interest payments based on one-month LIBOR. The purpose of the swap is to effectively convert a portion of AFG’s floating rate MBS to fixed rate by offsetting the variability in cash flows attributable to changes in one-month LIBOR. The notional amount of the swap amortizes down over its five-year life in anticipation of an expected decline in AFG’s portfolio of MBS with interest rates based on one-month LIBOR ($401 million notional amount at December 31, 2014). The fair value of the effective portion of the interest rate swap was less than $1 million at December 31, 2014, and is included in AOCI. During 2014, $2 million was reclassified from AOCI to net investment income and there was no ineffectiveness recorded in Net Earnings.

Deferred_Policy_Acquisition_Co

Deferred Policy Acquisition Costs	12 Months Ended
	Dec. 31, 2014
Deferred Policy Acquisition Costs Disclosures [Abstract]
Deferred Policy Acquisition Costs	Deferred Policy Acquisition Costs
	A progression of deferred policy acquisition costs is presented below (in millions):
		P&C			Annuity and Other (*)
		Deferred			Deferred			Sales												Consolidated
		Costs			Costs			Inducements			PVFP			Unrealized			Total			Total
	Balance at December 31, 2011	$	189		$	916		$	189		$	144		$	(537	)	$	712		$	901
	Additions	438			212			15			—			—			227			665
	Amortization:
	Periodic amortization	(423		)	(148		)	(30		)	(17		)	—			(195		)	(618		)
	Annuity unlocking	—			(33		)	(4		)	—			—			(37		)	(37		)
	Loss recognition charge	—			(67		)	—			(12		)	—			(79		)	(79		)
	Included in realized gains	—			(1		)	—			—			—			(1		)	(1		)
	Sale of subsidiaries	—			(92		)	—			(16		)	—			(108		)	(108		)
	Change in unrealized	—			—			—			—			(173		)	(173		)	(173		)
	Balance at December 31, 2012	204			787			170			99			(710		)	346			550
	Additions	468			222			11			—			—			233			701
	Amortization:
	Periodic amortization	(460		)	(140		)	(30		)	(14		)	—			(184		)	(644		)
	Annuity unlocking	—			4			(2		)	—			—			2			2
	Included in realized gains	—			2			—			—			—			2			2
	Foreign currency translation	(1		)	—			—			—			—			—			(1		)
	Change in unrealized	—			—			—			—			365			365			365
	Balance at December 31, 2013	211			875			149			85			(345		)	764			975
	Additions	497			198			8			—			—			206			703
	Amortization:
	Periodic amortization	(485		)	(130		)	(26		)	(11		)	—			(167		)	(652		)
	Annuity unlocking	—			(20		)	—			—			—			(20		)	(20		)
	Included in realized gains	—			2			1			—			—			3			3
	Foreign currency translation	(2		)	—			—			—			—			—			(2		)
	Change in unrealized	—			—			—			—			(186		)	(186		)	(186		)
	Balance at December 31, 2014	$	221		$	925		$	132		$	74		$	(531	)	$	600		$	821
	(*)	Includes AFG’s run-off long-term care and life segment and Medicare supplement and critical illness segment (sold in August 2012).
	The present value of future profits (“PVFP”) amounts in the table above are net of $209 million and $198 million of accumulated amortization at December 31, 2014 and 2013, respectively. The loss recognition charge recorded in the fourth quarter of 2012 for AFG’s closed block of long-term care insurance resulted in the write off of all remaining deferred policy acquisition costs for this business. During each of the next five years, the PVFP is expected to decrease at a rate of approximately one-sixth of the balance at the beginning of each respective year.

Managed_Investment_Entities

Managed Investment Entities	12 Months Ended
	Dec. 31, 2014
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]
Managed Investment Entities	Managed Investment Entities
	AFG is the investment manager and its subsidiaries have investments ranging from 15.0% to 51.2% of the most subordinate debt tranche of twelve collateralized loan obligation entities or “CLOs,” which are considered variable interest entities. AFG’s subsidiaries also own portions of the senior debt tranches of certain of these CLOs. Upon formation between 2004 and 2014, these entities issued securities in various senior and subordinate classes and invested the proceeds primarily in secured bank loans, which serve as collateral for the debt securities issued by each particular CLO. None of the collateral was purchased from AFG. AFG’s investments in the subordinate debt tranches of these entities receive residual income from the CLOs only after the CLOs pay expenses (including management fees to AFG), and interest on and returns of capital to senior levels of debt securities. There are no contractual requirements for AFG to provide additional funding for these entities. AFG has not provided and does not intend to provide any financial support to these entities.
	AFG’s maximum exposure to economic loss on its CLOs is limited to its investment in the CLOs, which had an aggregate fair value of $289 million (including $92 million invested in the most subordinate debt tranches) at December 31, 2014, and $271 million at December 31, 2013.
	In 2014, AFG formed two new CLOs, which issued an aggregate of $917 million face amount of liabilities (including $94 million face amount purchased by subsidiaries of AFG). During 2014, AFG subsidiaries also purchased $13 million face amount of senior debt tranches of existing CLOs for $13 million and received $81 million in redemption proceeds from its CLO investments. In 2013, AFG formed two new CLOs, which issued an aggregate of $829 million face amount of liabilities (including $85 million face amount purchased by subsidiaries of AFG). During 2013, AFG subsidiaries also purchased $94 million face amount of senior debt tranches of existing CLOs for $89 million and received $142 million in redemption proceeds from its CLO investments. In 2012, AFG formed two new CLOs, which issued an aggregate of $860 million face amount of liabilities (including $74 million face amount purchased by subsidiaries of AFG). During 2012, AFG subsidiaries also purchased $74 million face amount of senior debt tranches of existing CLOs for $69 million and received $12 million in redemption proceeds from its CLO investments. In 2014 and 2013, four and two AFG CLOs were substantially liquidated as permitted by the CLO indentures, respectively.
	The revenues and expenses of the CLOs are separately identified in AFG’s Statement of Earnings, after the elimination of management fees and earnings attributable to shareholders of AFG as measured by the change in the fair value of AFG’s investments in the CLOs. Selected financial information related to the CLOs is shown below (in millions):
		Year ended December 31,
		2014			2013			2012
	Gains (losses) on change in fair value of assets/liabilities (a):
	Assets	$	(66	)	$	11		$	95
	Liabilities	22			(25		)	(189		)
	Management fees paid to AFG	25			16			18
	CLO earnings (losses) attributable to (b):
	AFG shareholders	16			35			31
	Noncontrolling interests	(51		)	(26		)	(98		)
	(a)	Included in Revenues in AFG’s Statement of Earnings.
	(b)	Included in Earnings before income taxes in AFG’s Statement of Earnings.
	The aggregate unpaid principal balance of the CLOs’ fixed maturity investments exceeded the fair value of the investments by $83 million and $15 million at December 31, 2014 and 2013. The aggregate unpaid principal balance of the CLOs’ debt exceeded its fair value by $131 million and $109 million at those dates. The CLO assets include $2 million and $1 million in loans at December 31, 2014 and 2013, respectively, for which the CLOs are not accruing interest because the loans are in default (aggregate unpaid principal balance of $6 million at both of those dates).

Goodwill_and_Other_Intangibles

Goodwill and Other Intangibles	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangibles	Goodwill and Other Intangibles
	Changes in the carrying value of goodwill during 2012, 2013 and 2014, by reporting segment, are presented in the following table (in millions):
		Property and		Annuity			Total
		Casualty
	Balance at January 1, 2012	$	152	$	34		$	186
	Sale of subsidiary in 2012	—		(1		)	(1		)
	Balance at December 31, 2012 and 2013	152		33			185
	Acquisition of subsidiary in 2014	16		—			16
	Balance at December 31, 2014	$	168	$	33		$	201
	In the second quarter of 2014, goodwill increased by $16 million due to the purchase of Summit as discussed in Note B — “Acquisitions and Sales of Businesses.” In the third quarter of 2012, goodwill decreased $1 million due to the sale of a small annuity subsidiary.
	Included in other assets in AFG’s Balance Sheet is $49 million at December 31, 2014 and $14 million at December 31, 2013 of amortizable intangible assets related to property and casualty insurance acquisitions. These amounts are net of accumulated amortization of $91 million and $75 million, respectively. The increase in amortizable intangible assets in 2014 reflects the acquisition of Summit in April 2014 (see Note B — “Acquisitions and Sales of Businesses”) and a renewal rights intangible asset established in connection with the acquisition of a small property and casualty book of business in the first quarter of 2014. Amortization of intangibles was $19 million in 2014 and $14 million in each of 2013 and 2012. Future amortization of intangibles (weighted average amortization period of 6 years) is estimated to be $8 million per year in each of 2015 through 2019 and $9 million thereafter.

LongTerm_Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt
	The carrying value of long-term debt consisted of the following at December 31 (in millions):
		2014		2013
	Direct Senior Obligations of AFG:
	9-7/8% Senior Notes due June 2019	$	350	$	350
	6-3/8% Senior Notes due June 2042	230		230
	5-3/4% Senior Notes due August 2042	125		125
	7% Senior Notes due September 2050	132		132
	Other	3		3
		840		840
	Direct Subordinated Obligations of AFG:
	6-1/4% Subordinated Debentures due September 2054	150		—
	Subsidiaries:
	Notes payable secured by real estate due 2015 through 2016	59		61
	National Interstate bank credit facility	12		12
		71		73
		$	1,061	$	913
	At December 31, 2014, scheduled principal payments on debt for the subsequent five years and thereafter were as follows: 2015 — $14 million; 2016 — $45 million; 2017 — $12 million; 2018 — none; 2019 — $350 million and thereafter — $640 million.
	As shown below at December 31 (in millions), the majority of AFG’s long-term debt is unsecured obligations of the holding company and its subsidiaries.
		2014		2013
	Senior unsecured obligations	$	852	$	852
	Subordinated unsecured obligations	150		—
	Obligations secured by real estate	59		61
		$	1,061	$	913
	AFG can borrow up to $500 million under its revolving credit facility which expires in December 2016. Amounts borrowed under this agreement bear interest at rates ranging from 1.00% to 1.875% (currently 1.375%) over LIBOR based on AFG’s credit rating. No amounts were borrowed under this facility at December 31, 2014 or December 31, 2013.
	National Interstate can borrow up to $100 million under its unsecured credit agreement, which expires in November 2017. At December 31, 2014, there was $12 million outstanding under this agreement, bearing interest at 1.20% (six-month LIBOR plus 0.875%).
	In September 2014, AFG issued $150 million in 6-1/4% Subordinated Debentures due 2054. The net proceeds of the offering will be used for general corporate purposes, which may include repurchases of AFG’s outstanding Common Stock or the redemption of all or a portion of AFG’s $132 million outstanding aggregate principal amount of 7% Senior Notes due September 2050, which become redeemable (at par) at AFG’s option beginning on September 30, 2015.
	In August 2013, AAG Holding redeemed its Variable Rate Subordinated Debentures at par value. In September 2013, an AFG subsidiary paid off its remaining secured borrowing balance at maturity.
	In June 2012, AFG issued $230 million in 6-3/8% Senior Notes due 2042 and used the proceeds to redeem the outstanding AAG Holding Company 7-1/2% and 7-1/4% Senior Debentures at par value in July 2012. In August 2012, AFG issued $125 million in 5-3/4% Senior Notes due 2042 and used the proceeds to redeem the outstanding AFG 7-1/8% Senior Debentures at par value in September 2012.
	Cash interest payments on long-term debt were $72 million in 2014, $71 million in 2013 and $75 million in 2012.

Shareholders_Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholders’ Equity
	AFG is authorized to issue 12.5 million shares of Voting Preferred Stock and 12.5 million shares of Nonvoting Preferred Stock, each without par value.
	Stock Incentive Plans   Under AFG’s stock incentive plans, employees of AFG and its subsidiaries are eligible to receive equity awards in the form of stock options, stock appreciation rights, restricted stock awards, restricted stock units and stock awards.
	At December 31, 2014, there were 10.2 million shares of AFG Common Stock reserved for issuance under AFG’s stock incentive plans. Options are granted with an exercise price equal to the market price of AFG Common Stock at the date of grant. Options generally become exercisable at the rate of 20% per year commencing one year after grant and expire ten years after the date of grant.
	Data for stock options issued under AFG’s stock incentive plans is presented below:
		Shares			Average				Average		Aggregate
					Exercise				Remaining		Intrinsic
					Price				Contractual		Value
									Term		(in millions)
	Outstanding at January 1, 2014	6,608,614			$	32.16
	Granted	1,047,375			$	56.47
	Exercised	(1,262,313	)		$	28.19
	Forfeited/Cancelled	(9,877	)		$	42.22
	Outstanding at December 31, 2014	6,383,799			$	36.92			5.8 years		$	152
	Options exercisable at December 31, 2014	3,465,644			$	30.04			4.1 years		$	106
	The total intrinsic value of options exercised during 2014, 2013 and 2012 was $38 million, $35 million and $25 million, respectively. During 2014, 2013 and 2012, AFG received $35 million, $44 million and $40 million, respectively, in cash from the exercise of stock options. The total tax benefit related to the exercises was $12 million, $11 million and $8 million, respectively.
	AFG uses the Black-Scholes option pricing model to calculate the fair value of its option grants. The expected dividend yield is based on AFG’s current dividend rate. To determine expected volatility, AFG considers its daily historical volatility as well as implied volatility on traded options. The expected term was estimated based on historical exercise patterns and post vesting cancellations. The risk-free rate for periods associated with the expected term is based upon the U.S. Treasury yield curve in effect on the grant date.
		2014				2013				2012
	Exercise price	$	56.47			$	44.01			$	38.1
	Expected dividend yield	1.6		%		1.8		%		1.8		%
	Expected volatility	26		%		39		%		39		%
	Expected term (in years)	7.25				7.25				7.25
	Risk-free rate	2.2		%		1.36		%		1.4		%
	Grant date fair value	$	14.66			$	15.1			$	13.02
	The restricted Common Stock that AFG has granted generally vests over a three or four year period. Data relating to grants of restricted stock is presented below:
		Shares			Average
					Grant Date
					Fair Value
	Outstanding at January 1, 2014	552,569			$	37.79
	Granted	102,330			$	56.44
	Vested	(139,449	)		$	31.05
	Outstanding at December 31, 2014	515,450			$	43.32
	AFG issued 84,036 shares of Common Stock (fair value of $57.16 per share) in the first quarter of 2014 and 88,602 shares (fair value of $47.12 per share) in the first quarter of 2013 under its Equity Bonus Plan.
	Total compensation expense related to stock incentive plans of AFG and its subsidiaries for 2014, 2013 and 2012 was $25 million, $36 million and $26 million, respectively. Related tax benefits totaled $8 million in 2014, $12 million in 2013 and $8 million in 2012. At December 31, 2014, there was $30 million and $11 million of unrecognized compensation expense related to nonvested stock options and restricted stock awards, respectively. These amounts are expected to be recognized over a weighted average of 3.2 and 2.3 years, respectively.
	Accumulated Other Comprehensive Income, Net of Tax (“AOCI”)   Comprehensive income is defined as all changes in Shareholders’ Equity except those arising from transactions with shareholders. Comprehensive income includes net earnings and other comprehensive income, which consists primarily of changes in net unrealized gains or losses on available for sale securities.
	The progression of the components of accumulated other comprehensive income follows (in millions):
						Other Comprehensive Income
		AOCI				Pretax				Tax			Net			Attributable to			Attributable to			Other (c)			AOCI
		Beginning											of			noncontrolling			shareholders						Ending
		Balance											tax			interests									Balance
	Year ended December 31, 2014
	Net unrealized gains on securities:
	Unrealized holding gains (losses) on securities arising during the period					$	334			$	(118	)	$	216		$	(4	)	$	212
	Reclassification adjustment for realized (gains) losses included in net earnings (a)					(52		)		19			(33		)	1			(32		)
	Total net unrealized gains on securities (b)	$	563			282				(99		)	183			(3		)	180			$	—		$	743
	Foreign currency translation adjustments	1				(9		)		—			(9		)	—			(9		)	—			(8		)
	Pension and other postretirement plans adjustments	(4		)		(6		)		2			(4		)	—			(4		)	—			(8		)
	Total	$	560			$	267			$	(97	)	$	170		$	(3	)	$	167		$	—		$	727
	Year ended December 31, 2013
	Net unrealized gains on securities:
	Unrealized holding gains (losses) on securities arising during the period					$	(188	)		$	66		$	(122	)	$	4		$	(118	)
	Reclassification adjustment for realized (gains) losses included in net earnings (a)					(222		)		78			(144		)	2			(142		)
	Total net unrealized gains on securities (b)	$	823			(410		)		144			(266		)	6			(260		)	$	—		$	563
	Foreign currency translation adjustments	14				(13		)		—			(13		)	—			(13		)	—			1
	Pension and other postretirement plans adjustments	(6		)		3				(1		)	2			—			2			—			(4		)
	Total	$	831			$	(420	)		$	143		$	(277	)	$	6		$	(271	)	$	—		$	560
	Year ended December 31, 2012
	Net unrealized gains on securities (b)	$	578			$	388			$	(136	)	$	252		$	(7	)	$	245		$	—		$	823
	Foreign currency translation adjustments	10				6				—			6			(1		)	5			(1		)	14
	Pension and other postretirement plans adjustments	(8		)		2				—			2			—			2			—			(6		)
	Total	$	580			$	396			$	(136	)	$	260		$	(8	)	$	252		$	(1	)	$	831
	(a)	The reclassification adjustment out of net unrealized gains on securities affected the following lines in AFG’s Consolidated Statement of Earnings:
		OCI component		Affected line in the Consolidated Statement of Earnings
		Pretax		Realized gains on securities
	Tax		Provision for income taxes
	Attributable to noncontrolling interests		Net earnings (loss) attributable to noncontrolling interests
(b)	Includes net unrealized gains of $58 million at December 31, 2014 compared to net unrealized gains of $54 million and $33 million at December 31, 2013 and 2012, related to securities for which only the credit portion of an other-than-temporary impairment has been recorded in earnings.
(c)	Other relates to the 2012 acquisition of noncontrolling interest in a subsidiary.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	The following is a reconciliation of income taxes at the statutory rate of 35% to the provision for income taxes as shown in the Statement of Earnings (dollars in millions):
		2014							2013						2012
		Amount				% of EBT			Amount				% of EBT		Amount			% of EBT
	Earnings before income taxes (“EBT”)	$	626						$	689					$	537
	Income taxes at statutory rate	$	219			35	%		$	241			35	%	$	188		35	%
	Effect of:
	Tax exempt interest	(25		)		(4	%)		(21		)		(3	%)	(23		)	(4	%)
	Losses of managed investment entities	18				3	%		9				1	%	34			6	%
	Change in valuation allowance	7				1	%		1				—	%	3			1	%
	Subsidiaries not in AFG’s tax return	1				—	%		2				—	%	(1		)	—	%
	Tax case and settlement of open tax years	—				—	%		—				—	%	(67		)	(13	%)
	Other	—				—	%		4				1	%	1			—	%
	Provision for income taxes as shown in the Statement of Earnings	$	220			35	%		$	236			34	%	$	135		25	%
	A decision in favor of AFG from litigation with the IRS regarding the calculation of tax reserves for certain annuity liabilities became final in August 2012. As a result, during the third quarter of 2012, AFG recorded net earnings of approximately $28 million, which included the expected refund of $17 million of tax and interest paid to the IRS in 2005 and 2006 as well as a decrease in the liability for uncertain tax positions. In December 2012, AFG reached an agreement with the IRS to close subsequent years held open by the tax case. As a result, AFG decreased its tax liabilities by approximately $39 million in the fourth quarter of 2012.
	AFG’s 2012 — 2014 tax years remain subject to examination by the IRS.
	Total earnings before income taxes include losses subject to tax in foreign jurisdictions of less than $1 million in 2014 compared to income of $12 million in 2013 and losses of $3 million in 2012.
	The total income tax provision (credit) consists of (in millions):
		2014				2013				2012
	Current taxes:
	Federal	$	265			$	308			$	146
	State	8				5				6
	Deferred taxes:
	Federal	(53		)		(77		)		(17		)
	Provision for income taxes	$	220			$	236			$	135
	For income tax purposes, AFG and its subsidiaries had the following carryforwards available at December 31, 2014 (in millions):
		Expiring		Amount
	Operating Loss – U.S.	2017 - 2024		$	144
	Operating Loss – United Kingdom	indefinite		131			(*)
	(*)	£85 million
	Deferred income tax assets and liabilities reflect temporary differences between the carrying amounts of assets and liabilities recognized for financial reporting purposes and the amounts recognized for tax purposes. The significant components of deferred tax assets and liabilities included in the Balance Sheet at December 31 were as follows (in millions):
		2014				2013
	Deferred tax assets:
	Federal net operating loss carryforwards	$	51			$	51
	Foreign underwriting losses	56				50
	Insurance claims and reserves	746				558
	Employee benefits	107				98
	Other, net	26				51
	Total deferred tax assets before valuation allowance	986				808
	Valuation allowance against deferred tax assets	(109		)		(103		)
	Total deferred tax assets	877				705
	Deferred tax liabilities:
	Subsidiaries not in AFG’s tax return (*)	(61		)		(60		)
	Investment securities	(663		)		(443		)
	Deferred policy acquisition costs	(178		)		(234		)
	Total deferred tax liabilities	(902		)		(737		)
	Net deferred tax liability	$	(25	)		$	(32	)
	(*)    Related to National Interstate Corporation, a 51%-owned subsidiary.
	AFG’s net deferred tax liability at December 31, 2014 and 2013 is included in other liabilities in AFG’s Balance Sheet.
	The likelihood of realizing deferred tax assets is reviewed periodically; any adjustments required to the valuation allowance are made in the period during which developments requiring an adjustment become known.
	“Foreign underwriting losses” in the table above include the net operating loss carryforward and other deferred tax assets related to the Marketform Lloyd’s insurance business, which resulted primarily from underwriting losses in its run-off Italian public hospital medical malpractice business that has not been written since 2008. Due to uncertainty concerning the realization of the deferred tax benefits associated with these losses, AFG maintains a full valuation allowance of $56 million against these deferred tax assets at December 31, 2014. In addition to the valuation allowance related to the Marketform Lloyd’s insurance business, the gross deferred tax asset has also been reduced by a $50 million valuation allowance related to a portion of AFG’s net operating loss carryforwards (“NOL”) subject to the separate return limitation year (“SRLY”) tax rules. A SRLY NOL can be used only by the entity that created it and only in years that both it and the consolidated group have taxable income.
	The increase in the deferred tax assets related to insurance claims and reserves reflects growth in the annuity business, the April 2014 acquisition of Summit and the impact of the increase in unrealized gains on fixed maturity securities.
	The changes in the deferred tax liabilities related to investment securities and deferred policy acquisition costs at year end 2014 compared to 2013 are due primarily to the increase in unrealized gains on fixed maturity securities.
	In July 2014, AFG finalized a settlement with the IRS related to tax years 2008 and 2009. As a result, AFG’s uncertain tax positions are now effectively settled, allowing AFG to reduce its liability for previously uncertain tax positions by $19 million in the third quarter of 2014. Although AFG agreed to pay $11 million to the IRS, the majority of the reduction in this liability resulted in offsetting adjustments to AFG’s deferred tax liability and did not impact AFG’s effective tax rate. The portion of the reduction in this liability that favorably impacted the effective tax rate was approximately $4 million including interest. The reduction of the liability for previously uncertain tax positions includes $17 million related to the timing of recognition of investment income on certain debt securities and $2 million related to the deductibility of certain financing expenses.
	AFG increased its liability for uncertain tax positions by $1 million in 2013 and $3 million in 2012, exclusive of interest, for the uncertainty as to the timing of tax return inclusion of income related to certain securities. During 2012, AFG also increased its liability for uncertain tax positions by $2 million related to the deductibility of certain financing expenses.
	The resolution of the tax case and closure of subsequent tax years during 2012 (discussed above) also reduced AFG’s liability for uncertain tax positions by $36 million and the related liability for interest by $14 million. Additionally, the IRS issued new guidance during the third quarter of 2012 that brought certainty to the timing of investment deductions, which caused AFG to reduce its liability for uncertain tax positions by $10 million. Because this was solely a timing issue, the reduction in AFG’s liability for uncertain tax positions for this item was offset by an increase in AFG’s deferred tax liability with no overall impact on income tax expense.
	A progression of the liability for uncertain tax positions, excluding interest and penalties, follows (in millions):
		2014				2013				2012
	Balance at January 1	$	19			$	18			$	59
	Reductions for tax positions of prior years	(8		)		—				(46		)
	Additions for tax positions of current year	—				1				5
	Settlements	(11		)		—				—
	Balance at December 31	$	—			$	19			$	18
	AFG’s provision for income taxes included a benefit of $1 million in 2014, an expense of $1 million in 2013 and a benefit of $14 million in 2012 of interest (net of federal benefit or expense). AFG’s liability for interest related to unrecognized tax benefits was $1 million at December 31, 2013 (net of federal benefit); no penalties were accrued at that date.
Cash payments for income taxes, net of refunds, were $347 million, $204 million and $277 million for 2014, 2013 and 2012, respectively.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies
	Establishing property and casualty insurance reserves for claims related to environmental exposures, asbestos and other mass tort claims is subject to uncertainties that are significantly greater than those presented by other types of claims. For this group of claims, traditional actuarial techniques that rely on historical loss development trends cannot be used and a range of reasonably possible losses cannot be estimated. In addition, accruals (included in other liabilities) have been recorded for various environmental and occupational injury and disease claims and other contingencies arising out of the railroad operations disposed of by American Premier’s predecessor, Penn Central Transportation Company (“PCTC”) and its subsidiaries, prior to its bankruptcy reorganization in 1978 and certain manufacturing operations disposed of by American Premier and Great American Financial Resources, Inc. (“GAFRI”).
	AFG completed an in-depth internal review of its asbestos and environmental (“A&E”) exposures in the third quarter of 2014. The study resulted in A&E charges of $24 million for the property and casualty group and $6 million for the former railroad and manufacturing operations. In the third quarter of 2013, AFG completed a comprehensive study of its A&E exposures with the assistance of specialty actuarial, engineering and consulting firms and outside counsel. The study resulted in A&E charges of $54 million for the property and casualty group and $22 million for the former railroad and manufacturing operations. In the third quarter of 2012, AFG completed an in-depth internal review of its A&E exposures, which resulted in A&E charges of $31 million for the property and casualty group and $2 million for the former railroad and manufacturing operations.
	The insurance group’s liability for asbestos and environmental reserves was $366 million at December 31, 2014; related recoverables from reinsurers (net of allowances for doubtful accounts) at that date were $77 million.
	At December 31, 2014, American Premier and its subsidiaries had liabilities for environmental and personal injury claims and other contingencies aggregating $80 million. The environmental claims consist of a number of proceedings and claims seeking to impose responsibility for hazardous waste remediation costs related to certain sites formerly owned or operated by the railroad and manufacturing operations. Remediation costs are difficult to estimate for a number of reasons, including the number and financial resources of other potentially responsible parties, the range of costs for remediation alternatives, changing technology and the time period over which these matters develop. The personal injury claims and other contingencies include pending and expected claims, primarily by former employees of PCTC, for injury or disease allegedly caused by exposure to excessive noise, asbestos or other substances in the workplace and other labor disputes.
	At December 31, 2014, GAFRI had a liability of approximately $10 million for environmental costs and certain other matters associated with the sales of its former manufacturing operations.
	While management believes AFG has recorded adequate reserves for the items discussed above in this note, the outcome is uncertain and could result in liabilities that may vary from amounts AFG has currently recorded. Such amounts could have a material effect on AFG’s future results of operations and financial condition.
	In addition, AFG and its subsidiaries are involved in litigation from time to time, generally arising in the ordinary course of business. This litigation may include, but is not limited to, general commercial disputes, lawsuits brought by policyholders, employment matters, reinsurance collection matters and actions challenging certain business practices of insurance subsidiaries. None of these matters are expected to have a material adverse impact on AFG’s results of operations or financial condition.

Quarterly_Operating_Results_Un

Quarterly Operating Results (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Operating Results (Unaudited)	Quarterly Operating Results (Unaudited)
	The operations of certain AFG business segments are seasonal in nature. While insurance premiums are recognized on a relatively level basis, claim losses related to adverse weather (snow, hail, hurricanes, severe storms, tornadoes, etc.) may be seasonal. The profitability of AFG’s crop insurance business is primarily recognized during the second half of the year as crop prices and yields are determined. Quarterly results necessarily rely heavily on estimates. These estimates and certain other factors, such as the discretionary sales of assets, cause the quarterly results not to be necessarily indicative of results for longer periods of time.
	The following are quarterly results of consolidated operations for the two years ended December 31, 2014 (in millions, except per share amounts). Quarterly earnings per share do not add to year-to-date amounts due to changes in shares outstanding.
		1st		2nd			3rd			4th			Total
		Quarter		Quarter			Quarter			Quarter			Year
	2014
	Revenues	$	1,211	$	1,392		$	1,581		$	1,529		$	5,713
	Net earnings, including noncontrolling interests	107		83			91			125			406
	Net earnings attributable to shareholders	103		106			116			127			452
	Earnings attributable to shareholders per Common Share:
	Basic	$	1.15	$	1.18		$	1.3		$	1.44		$	5.07
	Diluted	1.13		1.15			1.28			1.41			4.97
	Average number of Common Shares:
	Basic	89.6		89.6			89			87.9			89
	Diluted	91.6		91.6			90.9			89.8			91
	2013
	Revenues	$	1,148	$	1,139		$	1,443		$	1,362		$	5,092
	Net earnings, including noncontrolling interests	113		77			98			165			453
	Net earnings attributable to shareholders	120		110			83			158			471
	Earnings attributable to shareholders per Common Share:
	Basic	$	1.34	$	1.23		$	0.94		$	1.77		$	5.27
	Diluted	1.32		1.2			0.92			1.73			5.16
	Average number of Common Shares:
	Basic	89.4		89.6			89.1			89.4			89.3
	Diluted	91		91.5			91			91.4			91.2
	Pretax realized gains on subsidiaries and securities (including other-than-temporary impairments) and favorable (adverse) prior year development of AFG’s liability for losses and loss adjustment expenses (“LAE”) were as follows (in millions):
		1st		2nd			3rd			4th			Total
		Quarter		Quarter			Quarter			Quarter			Year
	Realized Gains
	2014	$	19	$	12		$	13		$	8		$	52
	2013	57		41			56			63			217
	Prior Year Development Favorable (Adverse)
	2014	$	31	$	(14	)	$	(13	)	$	(10	)	$	(6	)
	2013	28		22			(40		)	5			15
	Adverse prior year development for the second quarter of 2014 includes $22 million of adverse reserve development in the property and transportation sub-segment, which resulted from an increase in claim severity in the commercial auto liability business, partially offset by lower than expected claim severity in the agricultural and property and inland marine businesses. Adverse prior year development for the third quarter of 2014 includes pretax special charges of $24 million to strengthen property and casualty insurance A&E reserves. Adverse prior year development in the fourth quarter of 2014 was due primarily to adverse reserve development at Marketform and higher than expected claim severity in contractor claims and in a run-off book of casualty business.
	Adverse prior year development for the third quarter of 2013 includes pretax special charges of $54 million to strengthen property and casualty insurance A&E reserves.
	Results for the third quarter of 2014 and 2013 include pretax special charges of $6 million and $22 million, respectively, to strengthen reserves for A&E exposures related to AFG’s former railroad and manufacturing operations.

Insurance

Insurance	12 Months Ended
	Dec. 31, 2014
Insurance [Abstract]
Insurance	Insurance
	Securities owned by U.S.-based insurance subsidiaries having a carrying value of approximately $1.18 billion at December 31, 2014, were on deposit as required by regulatory authorities. At December 31, 2014, AFG and its subsidiaries had $223 million in undrawn letters of credit (none of which was collateralized) supporting the underwriting capacity of its U.K.-based Lloyd’s insurer.
	Property and Casualty Insurance Reserves   The liability for losses and LAE for long-term scheduled payments under certain workers’ compensation insurance has been discounted at 4.5% at both December 31, 2014 and 2013, which represents an approximation of long-term investment yields. As a result, the total liability for losses and loss adjustment expenses at December 31, 2014 and 2013, has been reduced by $19 million and $20 million.
	The following table provides an analysis of changes in the liability for losses and loss adjustment expenses, net of reinsurance (and grossed up), over the past three years (in millions):
		2014			2013			2012
	Balance at beginning of period	$	4,288		$	4,129		$	4,282
	Provision for losses and LAE occurring in the current year	2,488			2,055			1,903
	Net increase (decrease) in provision for claims of prior years	6			(15		)	(30		)
	Total losses and LAE incurred	2,494			2,040			1,873
	Payments for losses and LAE of:
	Current year	(789		)	(739		)	(841		)
	Prior years	(1,340		)	(1,131		)	(1,185		)
	Total payments	(2,129		)	(1,870		)	(2,026		)
	Reserves of businesses acquired (*)	1,028			—			—
	Foreign currency translation and other	(36		)	(11		)	—
	Balance at end of period	5,645			4,288			4,129
	Add back reinsurance recoverables, net of allowance	2,227			2,122			2,716
	Gross unpaid losses and LAE included in the Balance Sheet	$	7,872		$	6,410		$	6,845
	(*)   Reflects the acquisition of Summit in April 2014 (see Note B — “Acquisitions and Sales of Businesses”).
	Net adverse development in 2014 reflects higher than expected severity in commercial auto liability losses written in the transportation businesses (within the Property and transportation sub-segment), higher than expected claims severity in contractor claims and in a run-off book of casualty business and adverse reserve development at Marketform (all within the Specialty casualty sub-segment), and the $24 million special charge to increase asbestos and environmental reserves. This adverse development was offset by (i) lower than expected claim severity in directors and officers liability insurance, lower than expected claim severity and frequency in excess liability insurance and lower than anticipated claim severity in specialty workers’ compensation business (all within the Specialty casualty sub-segment), and (ii) lower than expected claim severity in the surety and fidelity businesses and lower than expected claim frequency and severity in the foreign credit business and products for financial institutions (within the Specialty financial sub-segment).
	Favorable development in 2013 was due primarily to lower than expected severity in directors and officers liability insurance and lower than expected claim severity and frequency in the excess liability business (both within the Specialty casualty sub-segment) lower than expected frequency and severity in the foreign credit and financial institutions businesses (within the Specialty financial sub-segment) and favorable reserve development associated with AFG’s internal reinsurance program, partially offset by the $54 million special charge to increase asbestos and environmental reserves.
	Favorable development in 2012 was due primarily to lower than expected frequency and severity in the homebuilders’ general liability business (within the Specialty casualty sub-segment) and lower than expected frequency in the crop business (within the Property and transportation sub-segment), partially offset by higher frequency and severity in a block of program business (within the Specialty casualty sub-segment) and the $31 million special charge to increase asbestos and environmental reserves.
	Closed Block of Long-Term Care Insurance   AFG, as well as other companies that sell long-term care products, have accumulated relatively limited claims, lapse and mortality experience, making it difficult to predict future claims. Long-term care claims tend to be much higher in dollar amount and longer in duration than other health care products. In addition, long-term care claims are incurred much later in the life of a policy than most other health products. These factors made it difficult to appropriately price this product and were instrumental in AFG’s decision to stop writing new policies in January 2010. AFG’s outstanding long-term care policies have level premiums and are guaranteed renewable. Premium rates can potentially be increased in reaction to adverse experience; however, any rate increases would require regulatory approval.
	In 2012, AFG recorded a $153 million pretax loss recognition charge to write off deferred policy acquisition costs and strengthen reserves on its closed block of long-term care insurance, due primarily to the impact of changes in assumptions related to future investment yields resulting from the continued low interest rate environment, as well as changes in claims, expenses and persistency assumptions. No additional loss recognition charges were recorded in 2014 or 2013. At December 31, 2014, AFG’s long-term care insurance reserves were $807 million, net of reinsurance recoverables and excluding the impact of unrealized gains on securities.
	FHLB Funding Agreements   Great American Life Insurance Company (“GALIC”), a wholly-owned annuity subsidiary, is a member of the Federal Home Loan Bank of Cincinnati (“FHLB”). The FHLB makes advances and provides other banking services to member institutions. Members are required to purchase stock in the FHLB in addition to maintaining collateral deposits that back any funds advanced. GALIC’s $34 million investment in FHLB capital stock at December 31, 2014, is included in other investments at cost. Membership in the FHLB provides the annuity operations with a substantial additional source of liquidity. These advances further the FHLB’s mission of improving access to housing by increasing liquidity in the residential mortgage-backed securities market. In the second quarter of 2013, the FHLB advanced GALIC $200 million, (included in annuity benefits accumulated) increasing the total amount advanced to $440 million at both December 31, 2013 and December 31, 2014. Interest rates under the various funding agreements on these advances range from 0.02% to 0.23% over LIBOR (average rate of 0.32% at December 31, 2014). While these advances must be repaid between 2016 and 2018, GALIC has the option to prepay all or a portion of the advances. The advances on these agreements are collateralized by mortgage-backed securities with a fair value of $544 million (included in available for sale fixed maturity securities) at December 31, 2014. Interest credited on the funding agreements, which is included in annuity benefits, was $1 million in 2014 and 2013 and less than $1 million in 2012.
	Statutory Information   AFG’s U.S.-based insurance subsidiaries are required to file financial statements with state insurance regulatory authorities prepared on an accounting basis prescribed or permitted by such authorities (statutory basis). Net earnings and capital and surplus on a statutory basis for the insurance subsidiaries were as follows (in millions):
		Net Earnings									Capital and Surplus
		2014			2013			2012			2014		2013
	Property and casualty companies	$	318		$	332		$	221		$	2,286	$	1,896
	Life insurance companies	349			294			171			1,714		1,619
	The National Association of Insurance Commissioners’ (“NAIC”) model law for risk based capital (“RBC”) applies to both life and property and casualty insurance companies. RBC formulas determine the amount of capital that an insurance company needs so that it has an acceptable expectation of not becoming financially impaired. Companies below specific trigger points or ratios are subject to regulatory action. At December 31, 2014 and 2013, the capital ratios of all AFG insurance companies substantially exceeded the RBC requirements. AFG’s insurance companies did not use any prescribed or permitted statutory accounting practices that differed from the NAIC statutory accounting practices at December 31, 2014 or 2013.
	Payments of dividends by AFG’s insurance companies are subject to various state laws that limit the amount of dividends that can be paid. Under applicable restrictions, the maximum amount of dividends available to AFG in 2015 from its insurance subsidiaries without seeking regulatory clearance is $673 million. Additional amounts of dividends require regulatory approval.
	AFG paid common stock dividends to shareholders totaling $169 million, $161 million and $91 million in 2014, 2013 and 2012, respectively. Currently, there are no regulatory restrictions on AFG’s retained earnings or net income that materially impact its ability to pay dividends. Based on shareholders’ equity at December 31, 2014, AFG could pay dividends in excess of $1 billion without violating its most restrictive debt covenant. However, the payment of future dividends will be at the discretion of AFG’s Board of Directors and will be dependent on many factors including AFG’s financial condition and results of operations, the capital requirements of its insurance subsidiaries, and rating agency commitments.
	Reinsurance   In the normal course of business, AFG’s insurance subsidiaries cede reinsurance to other companies to diversify risk and limit maximum loss arising from large claims. To the extent that any reinsuring companies are unable to meet obligations under agreements covering reinsurance ceded, AFG’s insurance subsidiaries would remain liable. The following table shows (in millions) (i) amounts deducted from property and casualty written and earned premiums in connection with reinsurance ceded, (ii) written and earned premiums included in income for reinsurance assumed and (iii) reinsurance recoveries, which represent ceded losses and loss adjustment expenses.
		2014			2013			2012
	Direct premiums written	$	5,387		$	4,744		$	4,283
	Reinsurance assumed	90			61			38
	Reinsurance ceded	(1,457		)	(1,464		)	(1,372		)
	Net written premiums	$	4,020		$	3,341		$	2,949
	Direct premiums earned	$	5,195		$	4,684		$	4,120
	Reinsurance assumed	75			45			36
	Reinsurance ceded	(1,392		)	(1,525		)	(1,309		)
	Net earned premiums	$	3,878		$	3,204		$	2,847
	Reinsurance recoveries	$	895		$	1,255		$	1,743
	In March 2014, AFG’s property and casualty insurance operations entered into a reinsurance agreement to obtain additional catastrophe protection through a catastrophe bond structure with Riverfront Re Ltd. (“Riverfront”). The reinsurance agreement provides supplemental reinsurance coverage up to $95 million (fully collateralized) for catastrophe losses in excess of $100 million occurring during the period from April 1, 2014 through December 31, 2016. In connection with the reinsurance agreement, Riverfront issued notes to unrelated investors for the full $95 million of coverage provided under the reinsurance agreement. At the time of the agreement, AFG concluded that Riverfront is a variable interest entity, but that it does not have a variable interest in the entity because the variability in Riverfront’s results is expected to be absorbed entirely by the investors in Riverfront. Accordingly, Riverfront is not consolidated in AFG’s financial statements and the reinsurance agreement is accounted for as ceded reinsurance. AFG’s cost for this coverage is approximately $5 million per year.
	AFG has reinsured approximately $12.70 billion of its $16.71 billion in face amount of life insurance at December 31, 2014 compared to $13.43 billion of its $17.98 billion in face amount of life insurance at December 31, 2013. Life written premiums ceded were $41 million, $44 million and $42 million for 2014, 2013 and 2012, respectively.
	Fixed Annuities   For certain products, the liability for “annuity benefits accumulated” includes reserves for excess benefits expected to be paid on future deaths and annuitizations (“EDAR”), guaranteed withdrawal benefits and accrued persistency and premium bonuses. The liabilities included in AFG’s Balance Sheet for these benefits, excluding the impact of unrealized gains on securities, were as follows at December 31 (in millions):
		2014			2013
	Excess death and annuitization	$	213		$	197
	Guaranteed withdrawal benefits	151			71
	Accrued persistency and premium bonuses	14			15
	Variable Annuities   At December 31, 2014, the aggregate guaranteed minimum death benefit value (assuming every variable annuity policyholder died on that date) on AFG’s variable annuity policies exceeded the fair value of the underlying variable annuities by $23 million, compared to $26 million at December 31, 2013. Death benefits paid in excess of the variable annuity account balances were less than $1 million in each of the last three years.

Additional_Information

Additional Information	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Additional Information	Additional Information
	AFG’s aggregate allowance for uncollectible reinsurance recoverables was $25 million and $27 million at December 31, 2014 and 2013, respectively. AFG reviews the allowance quarterly and adjusts it as necessary to reflect changes in estimates of uncollectible balances. In 2014, 2013 and 2012, AFG recorded charges against the allowance of $4 million, $1 million and less than $1 million, respectively (included in losses and loss adjustment expenses). In 2014, the allowance was reduced by reinsurance recoverable write-offs of $6 million.
	Operating Leases   Total rental expense for various leases of office space and equipment was $65 million in 2014, $57 million in 2013 and $51 million in 2012. Future minimum rentals, related principally to office space, required under operating leases having initial or remaining noncancelable lease terms in excess of one year at December 31, 2014, were as follows: 2015 – $62 million; 2016 – $59 million; 2017 – $50 million; 2018 – $42 million; 2019 – $38 million; and $174 million thereafter.
	Financial Instruments — Unfunded Commitments   On occasion, AFG and its subsidiaries have entered into financial instrument transactions that may present off-balance-sheet risks of both a credit and market risk nature. These transactions include commitments to fund loans, loan guarantees and commitments to purchase and sell securities or loans. At December 31, 2014, AFG and its subsidiaries had commitments to fund credit facilities and contribute capital to limited partnerships and limited liability corporations of approximately $370 million.
	Benefit Plans   AFG expensed approximately $30 million in 2014, $32 million in 2013 and $27 million in 2012 for its retirement and employee savings plans.

Condensed_Financial_Informatio

Condensed Financial Information of Parent Company	12 Months Ended
	Dec. 31, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Financial Information of Parent Company	AMERICAN FINANCIAL GROUP, INC. — PARENT ONLY
	SCHEDULE II — CONDENSED FINANCIAL INFORMATION OF REGISTRANT
	(In Millions)
	Condensed Balance Sheet
		December 31,
		2014			2013
	Assets:
	Cash and cash equivalents	$	292		$	523
	Investment in securities	58			53
	Investment in subsidiaries (a)	5,638			5,041
	Other investments	2			2
	Other assets	103			108
	Total assets	$	6,093		$	5,727
	Liabilities and Equity:
	Long-term debt	$	990		$	840
	Other liabilities	224			288
	Shareholders’ equity	4,879			4,599
	Total liabilities and equity	$	6,093		$	5,727
	Condensed Statement of Earnings
		Year ended December 31,
		2014			2013			2012
	Revenues:
	Dividends from subsidiaries	$	480		$	606		$	433
	Equity in undistributed earnings of subsidiaries	332			260			325
	Investment and other income	5			8			5
	Total revenues	817			874			763
	Costs and Expenses:
	Interest charges on intercompany borrowings	10			10			11
	Interest charges on other borrowings	69			67			61
	Other expenses	66			90			68
	Total costs and expenses	145			167			140
	Earnings before income taxes	672			707			623
	Provision for income taxes	220			236			135
	Net Earnings Attributable to Shareholders	$	452		$	471		$	488
	Condensed Statement of Comprehensive Income
	Net earnings attributable to shareholders	$	452		$	471		$	488
	Other comprehensive income (loss), net of tax	167			(271		)	252
	Total comprehensive income, net of tax	$	619		$	200		$	740
	________________________
	(a)	Investment in subsidiaries includes intercompany receivables and payables.
	Condensed Statement of Cash Flows
		Year ended December 31,
		2014			2013			2012
	Operating Activities:
	Net earnings attributable to shareholders	$	452		$	471		$	488
	Adjustments:
	Equity in net earnings of subsidiaries	(545		)	(579		)	(515		)
	Dividends from subsidiaries	451			543			417
	Other operating activities, net	14			(7		)	(10		)
	Net cash provided by operating activities	372			428			380
	Investing Activities:
	Capital contributions to subsidiaries	(431		)	(38		)	(274		)
	Returns of capital from subsidiaries	—			36			1
	Purchases of investments, property and equipment	(1		)	(2		)	(11		)
	Net cash used in investing activities	(432		)	(4		)	(284		)
	Financing Activities:
	Additional long-term borrowings	145			—			344
	Reductions of long-term debt	—			—			(115		)
	Issuances of Common Stock	42			50			44
	Repurchases of Common Stock	(191		)	(70		)	(415		)
	Cash dividends paid on Common Stock	(167		)	(160		)	(90		)
	Net cash used in financing activities	(171		)	(180		)	(232		)
	Net Change in Cash and Cash Equivalents	(231		)	244			(136		)
	Cash and cash equivalents at beginning of year	523			279			415
Cash and cash equivalents at end of year	$	292		$	523		$	279

Supplementary_Insurance_Inform

Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2014
Supplementary Insurance Information [Abstract]
Supplementary Insurance Information	AMERICAN FINANCIAL GROUP, INC. AND SUBSIDIARIES
	SCHEDULE III — SUPPLEMENTARY INSURANCE INFORMATION
	THREE YEARS ENDED DECEMBER 31, 2014
	(IN MILLIONS)
	Segment	Deferred policy acquisition costs		Reserves for future policy benefits, claims and unpaid losses and LAE		Unearned premiums		Net earned premiums		Net investment income			Benefits, claims, losses and settlement expenses		Amortization of deferred policy acquisition costs		Other operating expenses		Net written premiums (excluding life)
	2014
	Property and casualty insurance	$	221	$	7,872	$	1,956	$	3,878	$	294		$	2,494	$	485	$	746	$	4,020
	Annuity	564		23,764		—		—		1,136			648		155		83		—
	Run-off long-term care and life	36		2,175		—		108		82			164		6		34		74
	Other	—		—		—		—		(11		)	—		—		272		—
	Total	$	821	$	33,811	$	1,956	$	3,986	$	1,501		$	3,306	$	646	$	1,135	$	4,094
	2013
	Property and casualty insurance	$	211	$	6,410	$	1,757	$	3,204	$	263		$	2,040	$	460	$	607	$	3,341
	Annuity	723		20,944		—		—		1,034			531		144		103		—
	Run-off long-term care and life	41		2,008		—		114		76			160		6		38		76
	Other	—		—		—		—		(27		)	—		—		314		—
	Total	$	975	$	29,362	$	1,757	$	3,318	$	1,346		$	2,731	$	610	$	1,062	$	3,417
	2012
	Property and casualty insurance	$	204	$	6,845	$	1,651	$	2,847	$	275		$	1,873	$	423	$	528	$	2,949
	Annuity	299		17,609		—		—		976			541		163		68		—
	Run-off long-term care and life	47		2,059		—		119		69			225		95		28		79
	Medicare supplement and critical illness	—		—		—		199		7			131		19		34		199
	Other	—		—		—		—		(26		)	—		—		292		—
	Total	$	550	$	26,513	$	1,651	$	3,165	$	1,301		$	2,770	$	700	$	950	$	3,227

Accounting_Policies_Policies

Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation   The consolidated financial statements include the accounts of American Financial Group, Inc. (“AFG”) and its subsidiaries. Certain reclassifications have been made to prior years to conform to the current year’s presentation. All significant intercompany balances and transactions have been eliminated. The results of operations of companies since their formation or acquisition are included in the consolidated financial statements. Events or transactions occurring subsequent to December 31, 2014, and prior to the filing of this Form 10-K, have been evaluated for potential recognition or disclosure herein.
	The preparation of the financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Changes in circumstances could cause actual results to differ materially from those estimates.
Fair Value Measurements	Fair Value Measurements   Accounting standards define fair value as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants on the measurement date. The standards establish a hierarchy of valuation techniques based on whether the assumptions that market participants would use in pricing the asset or liability (“inputs”) are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect AFG’s assumptions about the assumptions market participants would use in pricing the asset or liability. Other than the recording of the acquisition of Summit Holding Southeast, Inc. and its related companies (see Note B — “Acquisitions and Sales of Businesses”), AFG did not have any significant nonrecurring fair value measurements of nonfinancial assets and liabilities in 2014 or 2013.
Investments	Investments   Fixed maturity and equity securities classified as “available for sale” are reported at fair value with unrealized gains and losses included in accumulated other comprehensive income (“AOCI”) in AFG’s Balance Sheet. Fixed maturity and equity securities classified as “trading” are reported at fair value with changes in unrealized holding gains or losses during the period included in net investment income. Mortgage and policy loans are carried primarily at the aggregate unpaid balance.
	Premiums and discounts on fixed maturity securities are amortized using the interest method; mortgage-backed securities (“MBS”) are amortized over a period based on estimated future principal payments, including prepayments. Prepayment assumptions are reviewed periodically and adjusted to reflect actual prepayments and changes in expectations.
	Gains or losses on securities are determined on the specific identification basis. When a decline in the value of a specific investment is considered to be other-than-temporary at the balance sheet date, a provision for impairment is charged to earnings (included in realized gains (losses) on securities) and the cost basis of that investment is reduced. If management can assert that it does not intend to sell an impaired fixed maturity security and it is not more likely than not that it will have to sell the security before recovery of its amortized cost basis, then the other-than-temporary impairment is separated into two components: (i) the amount related to credit losses (recorded in earnings) and (ii) the amount related to all other factors (recorded in other comprehensive income). The credit-related portion of an other-than-temporary impairment is measured by comparing a security’s amortized cost to the present value of its current expected cash flows discounted at its effective yield prior to the impairment charge. Both components are shown in the Statement of Earnings. If management intends to sell an impaired security, or it is more likely than not that it will be required to sell the security before recovery, an impairment charge to earnings is recorded to reduce the amortized cost of that security to fair value.
Derivatives	Derivatives   Derivatives included in AFG’s Balance Sheet are recorded at fair value. Changes in fair value of derivatives are included in earnings, unless the derivatives are designated as cash flow hedges. Derivatives that do not qualify for hedge accounting under GAAP consist primarily of (i) components of certain fixed maturity securities (primarily interest-only MBS) and (ii) the equity-based component of certain annuity products (included in annuity benefits accumulated) and related call options (included in other investments) designed to be consistent with the characteristics of the liabilities and used to mitigate the risk embedded in those annuity products.
	To qualify for hedge accounting, at the inception of a derivative contract, AFG formally documents the relationship between the terms of the hedge and the hedged items and its risk management objective. This documentation includes defining how hedge effectiveness and ineffectiveness will be measured on a retrospective and prospective basis. Changes in the fair value of derivatives that are designated and qualify as highly effective cash flow hedges are recorded in AOCI and are reclassified into earnings when the variability of the cash flows from the hedged items impact earnings. Any hedge ineffectiveness is immediately recorded in current period earnings. When the change in the fair value of a qualifying cash flow hedge is included in earnings, it is included in the same line item in the Consolidated Statement of Earnings as the cash flows from the hedged item. Qualifying highly effective cash flow hedges include interest rate swaps, which are used to mitigate interest rate risk related to certain floating-rate securities included in AFG’s portfolio of fixed maturity securities.
Goodwill	Goodwill   Goodwill represents the excess of cost of subsidiaries over AFG’s equity in their underlying net assets. Goodwill is not amortized, but is subject to an impairment test at least annually. An entity is not required to complete the quantitative annual goodwill impairment test on a reporting unit if the entity elects to perform a qualitative analysis and determines that it is more likely than not that the reporting unit’s fair value exceeds its carrying amount.
Reinsurance	Reinsurance   Amounts recoverable from reinsurers are estimated in a manner consistent with the claim liability associated with the reinsured policies. AFG’s property and casualty insurance subsidiaries report as assets (i) the estimated reinsurance recoverable on paid and unpaid losses, including an estimate for losses incurred but not reported, and (ii) amounts paid or due to reinsurers applicable to the unexpired terms of policies in force. Payable to reinsurers includes ceded premiums due to reinsurers as well as ceded premiums retained by AFG’s property and casualty insurance subsidiaries under contracts to fund ceded losses as they become due. AFG’s insurance subsidiaries also assume reinsurance from other companies. Earnings on reinsurance assumed is recognized based on information received from ceding companies.
	A subsidiary cedes life insurance policies to a third party on a funds withheld basis whereby the subsidiary retains the assets (securities) associated with the reinsurance contract. Interest is credited to the reinsurer based on the actual investment performance of the retained assets. This reinsurance contract is considered to contain an embedded derivative (that must be adjusted to fair value) because the yield on the payable is based on a specific block of the ceding company’s assets, rather than the overall creditworthiness of the ceding company. AFG determined that changes in the fair value of the underlying portfolio of fixed maturity securities is an appropriate measure of the value of the embedded derivative. The securities related to this contract are classified as “trading.” The adjustment to fair value on the embedded derivative offsets the investment income recorded on the adjustment to fair value of the related trading portfolio.
Deferred Policy Acquisition Costs (''DPAC'')	Deferred Policy Acquisition Costs (“DPAC”)   Policy acquisition costs (principally commissions, premium taxes and certain underwriting and policy issuance costs) directly related to the successful acquisition or renewal of an insurance contract are deferred. DPAC also includes capitalized costs associated with sales inducements offered to fixed annuity policyholders such as enhanced interest rates and premium and persistency bonuses.
	For the property and casualty companies, DPAC is limited based upon recoverability without any consideration for anticipated investment income and is charged against income ratably over the terms of the related policies. A premium deficiency is recognized if the sum of expected claims costs, claims adjustment expenses and unamortized acquisition costs exceed the related unearned premiums. A premium deficiency is first recognized by charging any unamortized acquisition costs to expense to the extent required to eliminate the deficiency. If the premium deficiency is greater than unamortized acquisition costs, a liability is accrued for the excess deficiency and reported with unpaid losses and loss adjustment expenses.
	DPAC related to annuities is deferred to the extent deemed recoverable and amortized, with interest, in relation to the present value of actual and expected gross profits on the policies. Expected gross profits consist principally of estimated future investment margin (estimated future net investment income less interest credited on policyholder funds) and surrender, mortality, and other life and annuity policy charges, less death, annuitization and guaranteed withdrawal benefits in excess of account balances and estimated future policy administration expenses. To the extent that realized gains and losses result in adjustments to the amortization of DPAC related to annuities, such adjustments are reflected as components of realized gains (losses) on securities.
	DPAC related to traditional life and health insurance is amortized over the expected premium paying period of the related policies, in proportion to the ratio of annual premium revenues to total anticipated premium revenues. See “Life, Accident and Health Reserves” below for details on the impact of loss recognition on the accounting for traditional life and health insurance contracts.
	DPAC includes the present value of future profits on business in force of annuity and life, accident and health insurance companies acquired (“PVFP”). PVFP represents the portion of the costs to acquire companies that is allocated to the value of the right to receive future cash flows from insurance contracts existing at the date of acquisition. PVFP is amortized with interest in relation to expected gross profits of the acquired policies for annuities and universal life products and in relation to the premium paying period for traditional life and health insurance products.
	DPAC and certain other balance sheet amounts related to annuity, long-term care and life businesses are also adjusted, net of tax, for the change in expense that would have been recorded if the unrealized gains (losses) from securities had actually been realized. These adjustments are included in unrealized gains (losses) on marketable securities, a component of AOCI in AFG’s Balance Sheet.
Managed Investment Entities	Managed Investment Entities   A company is considered the primary beneficiary of, and therefore must consolidate, a variable interest entity (“VIE”) based primarily on its ability to direct the activities of the VIE that most significantly impact that entity’s economic performance and the obligation to absorb losses of, or receive benefits from, the entity that could potentially be significant to the VIE.
	AFG manages, and has investments in, collateralized loan obligations (“CLOs”) that are VIEs (see Note H — “Managed Investment Entities”). Both the management fees (payment of which is subordinate to other obligations of the CLOs) and the investments in the CLOs are considered variable interests. AFG has determined that it is the primary beneficiary of the CLOs because (i) its role as asset manager gives it the power to direct the activities that most significantly impact the economic performance of the CLOs and (ii) it has exposure to CLO losses (through its investments in the CLO debt tranches) and the right to receive benefits (through its subordinated management fees and returns on its investments), both of which could potentially be significant to the CLOs.
	Because AFG has no right to use the CLO assets and no obligation to pay the CLO liabilities, the assets and liabilities of the CLOs are shown separately in AFG’s Balance Sheet (at fair value). AFG has elected the fair value option for reporting on the CLO assets and liabilities to improve the transparency of financial reporting related to the CLOs. The excess of fair value of the CLOs’ assets over the fair value of the liabilities is recorded in AFG’s Balance Sheet as appropriated retained earnings — managed investment entities, representing amounts that ultimately will inure to the CLO debt holders.
	The net gain or loss from accounting for the CLO assets and liabilities at fair value is separately presented in AFG’s Statement of Earnings. CLO earnings attributable to AFG’s shareholders represent the change in fair value of AFG’s investments in the CLOs (including distributions) and management fees earned. All other CLO earnings (losses) are not attributable to AFG’s shareholders and will ultimately inure to the CLO debt holders. As a result, such CLO earnings (losses) are included in net earnings (loss) attributable to noncontrolling interests in AFG’s Statement of Earnings and in appropriated retained earnings — managed investment entities in the Balance Sheet. As the CLOs approach maturity (2016 to 2026), it is expected that earnings (losses) attributable to noncontrolling interests will reduce appropriated retained earnings towards zero as the fair values of the assets and liabilities converge and the CLO assets are used to pay the CLO debt.
	At December 31, 2014, assets and liabilities of managed investment entities included $17 million in assets and $12 million in liabilities of a temporary warehousing entity that was established in connection with the formation of a new CLO that is expected to close in the second quarter of 2015. Upon closing, all warehoused assets are expected to be transferred to the new CLO and the liabilities will be repaid.
	In August 2014, the FASB issued Accounting Standards Update (“ASU”) 2014-13 to address the diversity in practice regarding the accounting for assets and liabilities of a consolidated collateralized financing entity (such as a CLO) when an election has been made to account for that entity’s assets and liabilities at fair value. As discussed above, the fair values of a CLO’s assets may differ from the fair values of its liabilities even though the liabilities only have recourse to the assets, which results in “appropriated retained earnings — managed investment entities” in AFG’s Balance Sheet. Under ASU 2014-13, AFG will have the option to set the carrying value of the CLO liabilities equal to the fair value of the CLO assets (which have more observable fair values) as an alternative to reporting those liabilities at fair value. Under this alternative, CLO earnings attributable to AFG’s shareholders would continue to be measured by the change in the fair value of AFG’s investments in the CLOs and management fees earned. However, as a result of setting the carrying value of the CLO liabilities equal to the fair value of the CLO assets, there would no longer be any excess carrying value of CLO assets over the carrying value of CLO liabilities to be reported as “appropriated retained earnings — managed investment entities” in AFG’s Balance Sheet or any CLO earnings to be attributed to noncontrolling interests in AFG’s Statement of Earnings. If AFG elects to continue to measure both the CLO assets and liabilities at fair value, ASU 2014-13 will require amounts currently reflected as “appropriated retained earnings — managed investment entities” to be reclassified to unappropriated retained earnings in the Balance Sheet and amounts currently attributed to noncontrolling interests in the Statement of Earnings to be included in earnings attributable to AFG shareholders. Although ASU 2014-13 is not required to be adopted until 2016, AFG intends to early adopt the guidance effective January 1, 2015 (as permitted) and to elect the alternative measurement guidance on a modified retrospective basis. As a result, the amount reported as “appropriated retained earnings — managed investment entities” in AFG’s Balance Sheet at December 31, 2014 will effectively be reclassified to “liabilities of managed investment entities” on January 1, 2015. While the ASU will have an impact on the future presentation of individual CLO-related line items in AFG’s Statement of Earnings in future periods, it will have no overall impact on AFG’s net earnings attributable to shareholders.
Unpaid Losses and Loss Adjustment Expenses	Unpaid Losses and Loss Adjustment Expenses   The net liabilities stated for unpaid claims and for expenses of investigation and adjustment of unpaid claims represent management’s best estimate and are based upon (i) the accumulation of case estimates for losses reported prior to the close of the accounting period on direct business written; (ii) estimates received from ceding reinsurers and insurance pools and associations; (iii) estimates of unreported losses (including possible development on known claims) based on past experience; (iv) estimates based on experience of expenses for investigating and adjusting claims; and (v) the current state of the law and coverage litigation. Establishing reserves for asbestos, environmental and other mass tort claims involves considerably more judgment than other types of claims due to, among other things, inconsistent court decisions, an increase in bankruptcy filings as a result of asbestos-related liabilities, novel theories of coverage, and judicial interpretations that often expand theories of recovery and broaden the scope of coverage.
	Loss reserve liabilities are subject to the impact of changes in claim amounts and frequency and other factors. Changes in estimates of the liabilities for losses and loss adjustment expenses are reflected in the Statement of Earnings in the period in which determined. Despite the variability inherent in such estimates, management believes that the liabilities for unpaid losses and loss adjustment expenses are adequate.
Annuity Benefits Accumulated	Annuity Benefits Accumulated   Annuity receipts and benefit payments are recorded as increases or decreases in annuity benefits accumulated rather than as revenue and expense. Increases in this liability for interest credited are charged to expense and decreases for policy charges are credited to other income.
	For certain products, annuity benefits accumulated also includes reserves for accrued persistency and premium bonuses, guaranteed withdrawals and excess benefits expected to be paid on future deaths and annuitizations (“EDAR”). The liabilities for EDAR and guaranteed withdrawals are accrued for and modified using assumptions consistent with those used in determining DPAC and DPAC amortization, except that amounts are determined in relation to the present value of total expected assessments. Total expected assessments consist principally of estimated future investment margin, surrender, mortality, and other life and annuity policy charges, and unearned revenues once they are recognized as income.
	Annuity benefits accumulated also includes amounts advanced from the Federal Home Loan Bank of Cincinnati.
Unearned Revenue	Unearned Revenue   Certain upfront policy charges on annuities are deferred as unearned revenue (included in other liabilities) and recognized in net earnings using the same assumptions and estimated gross profits used to amortize DPAC.
Life, Accident and Health Reserves	Life, Accident and Health Reserves   Liabilities for future policy benefits under traditional life, accident and health policies are computed using the net level premium method. Computations are based on the original projections of investment yields, mortality, morbidity and surrenders and include provisions for unfavorable deviations unless a loss recognition event (premium deficiency) occurs. Claim reserves and liabilities established for accident and health claims are modified as necessary to reflect actual experience and developing trends.
	For long-duration contracts (such as traditional life and long-term care policies), loss recognition occurs when, based on current expectations as of the measurement date, existing contract liabilities plus the present value of future premiums (including reasonably expected rate increases) are not expected to cover the present value of future claims payments and related settlement and maintenance costs (excluding overhead) as well as unamortized acquisition costs. If a block of business is determined to be in loss recognition, a charge is recorded in earnings in an amount equal to the excess of the present value of expected future claims costs and unamortized acquisition costs over existing reserves plus the present value of expected future premiums (with no provision for adverse deviation). The charge is recorded first to reduce unamortized acquisition costs and then as an additional reserve (if unamortized acquisition costs have been reduced to zero).
	In addition, reserves for traditional life and long-term care policies are subject to adjustment for loss recognition charges that would have been recorded if the unrealized gains from securities had actually been realized. This adjustment is included in unrealized gains (losses) on marketable securities, a component of AOCI in AFG’s Balance Sheet.
Variable Annuity Assets and Liabilities	Variable Annuity Assets and Liabilities   Separate accounts related to variable annuities represent the fair value of deposits invested in underlying investment funds on which AFG earns a fee. Investment funds are selected and may be changed only by the policyholder, who retains all investment risk.
	AFG’s variable annuity contracts contain a guaranteed minimum death benefit (“GMDB”) to be paid if the policyholder dies before the annuity payout period commences. In periods of declining equity markets, the GMDB may exceed the value of the policyholder’s account. A GMDB liability is established for future excess death benefits using assumptions together with a range of reasonably possible scenarios for investment fund performance that are consistent with DPAC capitalization and amortization assumptions.
Premium Recognition	Premium Recognition   Property and casualty premiums are earned generally over the terms of the policies on a pro rata basis. Unearned premiums represent that portion of premiums written which is applicable to the unexpired terms of policies in force. On reinsurance assumed from other insurance companies or written through various underwriting organizations, unearned premiums are based on information received from such companies and organizations. For traditional life, accident and health products, premiums are recognized as revenue when legally collectible from policyholders. For interest-sensitive life and universal life products, premiums are recorded in a policyholder account, which is reflected as a liability. Revenue is recognized as amounts are assessed against the policyholder account for mortality coverage and contract expenses.
Noncontrolling Interests	Noncontrolling Interests   For Balance Sheet purposes, noncontrolling interests represents the interests of shareholders other than AFG in consolidated entities. In the Statement of Earnings, net earnings and losses attributable to noncontrolling interests represents such shareholders’ interest in the earnings and losses of those entities.
Income Taxes	Income Taxes   Deferred income taxes are calculated using the liability method. Under this method, deferred income tax assets and liabilities are determined based on differences between financial reporting and tax bases and are measured using enacted tax rates. A valuation allowance is established to reduce total deferred tax assets to an amount that will more likely than not be realized.
	AFG recognizes the tax benefits of uncertain tax positions only when the position is more likely than not to be sustained under examination by the appropriate taxing authority. Interest and penalties on AFG’s reserve for uncertain tax positions are recognized as a component of tax expense.
Stock-Based Compensation	Stock-Based Compensation   All share-based grants are recognized as compensation expense on a straight-line basis over their vesting periods based on their calculated fair value at the date of grant. AFG uses the Black-Scholes pricing model to measure the fair value of employee stock options. See Note K — “Shareholders’ Equity” for further information.
Benefit Plans	Benefit Plans   AFG provides retirement benefits to qualified employees of participating companies through the AFG 401(k) Retirement and Savings Plan, a defined contribution plan. AFG makes all contributions to the retirement fund portion of the plan and matches a percentage of employee contributions to the savings fund. Company contributions are expensed in the year for which they are declared. AFG and many of its subsidiaries provide health care and life insurance benefits to eligible retirees. AFG also provides postemployment benefits to former or inactive employees (primarily those on disability) who were not deemed retired under other company plans. The projected future cost of providing these benefits is expensed over the period employees earn such benefits.
Earnings Per Share	Earnings Per Share   Although basic earnings per share only considers shares of common stock outstanding during the period, the calculation of diluted earnings per share includes the following adjustments to weighted average common shares related to stock-based compensation plans: 2014 – 2.0 million, 2013 – 1.9 million and 2012 – 1.7 million.
	AFG’s weighted average diluted shares outstanding excludes the following anti-dilutive potential common shares related to stock compensation plans: 2014 – 1.0 million, 2013 – 1.1 million and 2012 – 1.8 million. Adjustments to net earnings attributable to shareholders in the calculation of diluted earnings per share were nominal in the 2014, 2013 and 2012 periods.
Statement of Cash Flows	Statement of Cash Flows   For cash flow purposes, “investing activities” are defined as making and collecting loans and acquiring and disposing of debt or equity instruments and property and equipment. “Financing activities” include obtaining resources from owners and providing them with a return on their investments, borrowing money and repaying amounts borrowed. Annuity receipts, surrenders, benefits and withdrawals are also reflected as financing activities. All other activities are considered “operating.” Short-term investments having original maturities of three months or less when purchased are considered to be cash equivalents for purposes of the financial statements.

Acquisitions_and_Sales_of_Busi1

Acquisitions and Sales of Businesses (Tables)	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Schedule of estimated fair values of assets acquired and liabilities assumed	The allocation of the purchase price is shown in the table below (in millions):
	Total purchase price				$	259
	Tangible assets acquired:
	Cash and cash equivalents	$	1,078
	Fixed maturities, available for sale	92
	Recoverables from reinsurers	116
	Agents’ balances and premiums receivable	41
	Deferred tax assets, net (a)	67
	Other receivables	21
	Other assets	11
	Total tangible assets acquired				1,426
	Liabilities acquired:
	Unpaid losses and loss adjustment expenses	1,142
	Unearned premiums	3
	Payable to reinsurers	3
	Other liabilities	66
	Total liabilities acquired				1,214
	Net tangible assets acquired, at fair value				212
	Excess purchase price over net tangible assets acquired				$	47
	Allocation of excess purchase price:
	Intangible assets acquired (b)				$	47
	Deferred tax on intangible assets acquired (a)				(16		)
	Goodwill				16
					$	47
	(a)	Included with AFG’s net deferred tax liabilities, which are included in Other liabilities in AFG’s Consolidated Balance Sheet.
	(b)	Included in Other assets in AFG’s Consolidated Balance Sheet.
Summarized financial information	The impact of the August 2012 sale of the Medicare supplement and critical illness segment on AFG’s financial statements is shown below (in millions):
		2012
	Sale proceeds	$	326
	Expenses	(11		)
	Net proceeds	$	315
	Assets of businesses sold:
	Cash and investments	$	217
	Deferred policy acquisition costs	108
	Other assets	31
	Total assets	356
	Liabilities of businesses sold:
	Life, accident and health reserves	209
	Other liabilities	2
	Total liabilities	211
	Net assets of businesses sold	$	145
	Gain on sale of subsidiaries	$	170

Segments_of_Operations_Tables

Segments of Operations (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Reporting Information, by Segment	The following tables (in millions) show AFG’s assets, revenues and earnings before income taxes by segment and sub-segment.
		2014			2013			2012
	Assets
	Property and casualty insurance (a)	$	14,069		$	11,717		$	12,163
	Annuity	27,317			24,294			20,909
	Run-off long-term care and life	2,489			2,408			2,304
	Other	3,660			3,668			3,795
	Total assets	$	47,535		$	42,087		$	39,171
	Revenues
	Property and casualty insurance:
	Premiums earned:
	Specialty
	Property and transportation	$	1,544		$	1,521		$	1,423
	Specialty casualty	1,765			1,135			948
	Specialty financial	469			469			405
	Other specialty	100			79			71
	Total premiums earned	3,878			3,204			2,847
	Net investment income	294			263			275
	Other income	9			15			24
	Total property and casualty insurance	4,181			3,482			3,146
	Annuity:
	Net investment income	1,136			1,034			976
	Other income	78			67			52
	Total annuity	1,214			1,101			1,028
	Run-off long-term care and life	194			194			191
	Medicare supplement and critical illness (b)	—			—			212
	Other	72			98			9
	Total revenues before realized gains (losses)	5,661			4,875			4,586
	Realized gains on securities	52			221			210
	Realized gains (losses) on subsidiaries	—			(4		)	161
	Total revenues	$	5,713		$	5,092		$	4,957
	(a)   Not allocable to sub-segments.
	(b)   Sold in August 2012.
		2014			2013			2012
	Earnings Before Income Taxes
	Property and casualty insurance:
	Underwriting:
	Specialty
	Property and transportation	$	21		$	12		$	19
	Specialty casualty	136			102			53
	Specialty financial	64			67			44
	Other specialty	16			25			15
	Other lines (a)	(25		)	(61		)	(44		)
	Total underwriting	212			145			87
	Investment and other income, net	244			230			235
	Total property and casualty insurance	456			375			322
	Annuity (b)	328			323			256
	Run-off long-term care and life (c)	(10		)	(10		)	(157		)
	Medicare supplement and critical illness (d)	—			—			28
	Other (e)	(200		)	(216		)	(283		)
	Total earnings before realized gains (losses) and income taxes	574			472			166
	Realized gains on securities	52			221			210
	Realized gains (losses) on subsidiaries	—			(4		)	161
	Total earnings before income taxes	$	626		$	689		$	537
	(a)	Includes special charges to increase asbestos and environmental (“A&E”) reserves of $24 million, $54 million and $31 million in 2014, 2013 and 2012, respectively.
	(b)	Includes a $5 million charge in the second quarter of 2013 to cover expected assessments from state guaranty funds related to insolvency and liquidation of an unaffiliated life insurance company.
	(c)	Includes a loss recognition charge of $153 million in the fourth quarter of 2012.
	(d)	Sold in August 2012.
	(e)	Includes holding company expenses, special charges to increase A&E reserves ($6 million in 2014, $22 million in 2013 and $2 million in 2012) and losses of managed investment entities attributable to noncontrolling interests ($51 million in 2014, $26 million in 2013 and $98 million in 2012). Holding company expenses in 2012 also include an $8 million loss on retirement of debt and a $15 million charge for a labor matter related to AFG’s former railroad operations.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Assets and liabilities measured at fair value	Assets and liabilities measured and carried at fair value in the financial statements are summarized below (in millions):
		Level 1				Level 2			Level 3			Total
	31-Dec-14
	Assets:
	Available for sale (“AFS”) fixed maturities:
	U.S. Government and government agencies	$	164			$	174		$	15		$	353
	States, municipalities and political subdivisions	—				6,647			100			6,747
	Foreign government	—				194			—			194
	Residential MBS	—				4,142			300			4,442
	Commercial MBS	—				2,407			44			2,451
	Asset-backed securities (“ABS”)	—				3,661			226			3,887
	Corporate and other	36				12,078			546			12,660
	Total AFS fixed maturities	200				29,303			1,231			30,734
	Trading fixed maturities	12				254			—			266
	Equity securities	1,306				297			93			1,696
	Assets of managed investment entities (“MIE”)	174				2,903			31			3,108
	Variable annuity assets (separate accounts) (*)	—				662			—			662
	Other investments — derivatives	—				322			—			322
	Total assets accounted for at fair value	$	1,692			$	33,741		$	1,355		$	36,788
	Liabilities:
	Liabilities of managed investment entities	$	118			$	—		$	2,701		$	2,819
	Derivatives in annuity benefits accumulated	—				—			1,160			1,160
	Other liabilities — derivatives	—				13			—			13
	Total liabilities accounted for at fair value	$	118			$	13		$	3,861		$	3,992
	31-Dec-13
	Assets:
	Available for sale fixed maturities:
	U.S. Government and government agencies	$	147			$	152		$	15		$	314
	States, municipalities and political subdivisions	—				5,311			61			5,372
	Foreign government	—				208			—			208
	Residential MBS	—				3,994			316			4,310
	Commercial MBS	—				2,696			28			2,724
	Asset-backed securities	—				2,418			75			2,493
	Corporate and other	28				10,672			335			11,035
	Total AFS fixed maturities	175				25,451			830			26,456
	Trading fixed maturities	—				305			—			305
	Equity securities	1,023				125			31			1,179
	Assets of managed investment entities	266				2,592			30			2,888
	Variable annuity assets (separate accounts) (*)	—				665			—			665
	Other investments — derivatives	—				274			—			274
	Total assets accounted for at fair value	$	1,464			$	29,412		$	891		$	31,767
	Liabilities:
	Liabilities of managed investment entities	$	156			$	—		$	2,411		$	2,567
	Derivatives in annuity benefits accumulated	—				—			804			804
	Other liabilities — derivatives	—				10			—			10
	Total liabilities accounted for at fair value	$	156			$	10		$	3,215		$	3,381
	(*)   Variable annuity liabilities equal the fair value of variable annuity assets.
Fair value measurements, Levels 1 and 2 transfers	The transfers between Level 1 and Level 2 for the years ended December 31, 2014, 2013 and 2012 are reflected in the table below at fair value as of the end of the reporting period (dollars in millions):
		Level 2 To Level 1 Transfers																	Level 1 To Level 2 Transfers
		# of Transfers								Fair Value									# of Transfers							Fair Value
		2014			2013			2012		2014			2013			2012			2014	2013			2012			2014		2013		2012
	Perpetual preferred stocks	14			15			2		$	96		$	70		$	16		13	2			7			$	83	$	10	$	41
	Common stocks	—			2			—		—			35			—			7	—			—			26		—		—
	Redeemable preferred stocks	1			3			1		5			21			2			—	—			—			—		—		—
Unobservable inputs used by management in determining fair value of embedded derivatives	The following table presents information about the unobservable inputs used by management in determining fair value of these embedded derivatives. See Note F — “Derivatives.”
	Unobservable Input		Range
	Adjustment for insurance subsidiary’s credit risk		0.40% – 1.75% over the risk free rate
	Risk margin for uncertainty in cash flows		0.52% reduction in the discount rate
	Surrenders		4% – 16% of indexed account value
	Partial surrenders		2% – 6% of indexed account value
	Annuitizations		1% – 1.5% of indexed account value
	Deaths		1.5% – 3.0% of indexed account value
	Budgeted option costs		2.25% – 3.5% of indexed account value
Changes in balances of Level 3 financial assets and liabilities	Changes in balances of Level 3 financial assets and liabilities carried at fair value during 2014, 2013 and 2012 are presented below (in millions). The transfers into and out of Level 3 were due to changes in the availability of market observable inputs. All transfers are reflected in the table at fair value as of the end of the reporting period.
						Total realized/unrealized
						gains (losses) included in
		Balance at December 31, 2013				Net			Other			Purchases			Sales and			Transfer		Transfer				Balance at December 31, 2014
						income			comprehensive			and			settlements			into		out of
									income (loss)			issuances						Level 3		Level 3
	AFS fixed maturities:
	U.S. government agency	$	15			$	—		$	—		$	—		$	—		$	—	$	—			$	15
	State and municipal	61				(1		)	—			30			—			10		—				100
	Residential MBS	316				4			3			13			(31		)	111		(116		)		300
	Commercial MBS	28				(1		)	—			—			—			17		—				44
	Asset-backed securities	75				3			(2		)	99			(39		)	117		(27		)		226
	Corporate and other	335				2			13			102			(73		)	172		(5		)		546
	Equity securities	31				1			2			62			(9		)	22		(16		)		93
	Assets of MIE	30				(3		)	—			6			(2		)	—		—				31
	Liabilities of MIE (a)	(2,411		)		22			—			(817		)	505			—		—				(2,701		)
	Embedded derivatives (b)	(804		)		(182		)	—			(221		)	47			—		—				(1,160		)
	(a)	Total realized/unrealized gains (losses) included in net income includes gains of $50 million related to liabilities outstanding as of December 31, 2014. See Note H — “Managed Investment Entities.”
	(b)	Total realized/unrealized gains (losses) included in net income for the embedded derivatives reflects gains related to the unlocking of actuarial assumptions of $58 million in 2014.
						Total realized/unrealized
						gains (losses) included in
		Balance at December 31, 2012				Net			Other			Purchases			Sales and			Transfer		Transfer				Balance at December 31, 2013
						income			comprehensive			and			settlements			into		out of
									income (loss)			issuances						Level 3		Level 3
	AFS fixed maturities:
	U.S. government agency	$	20			$	(2	)	$	(3	)	$	—		$	—		$	—	$	—			$	15
	State and municipal	58				(1		)	(2		)	10			—			—		(4		)		61
	Residential MBS	371				5			24			6			(53		)	86		(123		)		316
	Commercial MBS	22				(1		)	(1		)	—			—			8		—				28
	Asset-backed securities	253				4			(3		)	12			(57		)	11		(145		)		75
	Corporate and other	236				1			(14		)	113			(17		)	24		(8		)		335
	Equity securities	37				(1		)	6			53			(12		)	—		(52		)		31
	Assets of MIE	40				(5		)	—			8			(7		)	—		(6		)		30
	Liabilities of MIE (a)	(2,745		)		(25		)	—			(728		)	1,068			—		19				(2,411		)
	Embedded derivatives (b)	(465		)		(182		)	—			(192		)	35			—		—				(804		)
	(a)	Total realized/unrealized gains (losses) included in net income includes gains of $7 million related to liabilities outstanding as of December 31, 2013. See Note H — “Managed Investment Entities.”
	(b)	Total realized/unrealized gains (losses) included in net income for the embedded derivatives reflects gains related to the unlocking of actuarial assumptions of $2 million in 2013.
						Total realized/unrealized
						gains (losses) included in
		Balance at December 31, 2011				Net			Other			Purchases			Sales and			Transfer		Transfer				Balance at December 31, 2012
						income			comprehensive			and			settlements			into		out of
									income (loss)			issuances						Level 3		Level 3
	AFS fixed maturities:
	U.S. government agency	$	—			$	—		$	—		$	20		$	—		$	—	$	—			$	20
	State and municipal	83				—			4			19			(7		)	8		(49		)		58
	Residential MBS	361				5			17			96			(45		)	228		(291		)		371
	Commercial MBS	19				1			2			—			—			—		—				22
	Asset-backed securities	228				7			8			55			(36		)	14		(23		)		253
	Corporate and other	291				3			9			86			(35		)	15		(133		)		236
	Trading fixed maturities	1				—			—			—			—			—		(1		)		—
	Equity securities	11				—			2			30			—			13		(19		)		37
	Assets of MIE	44				—			—			20			(14		)	13		(23		)		40
	Liabilities of MIE (a)	(2,593		)		(189		)	—			(793		)	830			—		—				(2,745		)
	Embedded derivatives (b)	(361		)		(57		)	—			(73		)	26			—		—				(465		)
	(a)	Total realized/unrealized gains (losses) included in net income includes losses of $125 million related to liabilities outstanding as of December 31, 2012. See Note H — “Managed Investment Entities.”
	(b)	Total realized/unrealized gains (losses) included in net income for the embedded derivatives reflects gains related to the unlocking of actuarial assumptions of $36 million in 2012.
Fair value of financial instruments	The carrying value and fair value of financial instruments that are not carried at fair value in the financial statements at December 31 are summarized below (in millions):
		Carrying				Fair			Level 1			Level 2			Level 3
		Value				Value
	2014
	Financial assets:
	Cash and cash equivalents	$	1,343			$	1,343		$	1,343		$	—		$	—
	Mortgage loans	1,117				1,124			—			—			1,124
	Policy loans	228				228			—			—			228
	Total financial assets not accounted for at fair value	$	2,688			$	2,695		$	1,343		$	—		$	1,352
	Financial liabilities:
	Annuity benefits accumulated (*)	$	23,561			$	23,187		$	—		$	—		$	23,187
	Long-term debt	1,061				1,180			—			1,106			74
	Total financial liabilities not accounted for at fair value	$	24,622			$	24,367		$	—		$	1,106		$	23,261
	2013
	Financial assets:
	Cash and cash equivalents	$	1,639			$	1,639		$	1,639		$	—		$	—
	Mortgage loans	781				779			—			—			779
	Policy loans	238				238			—			—			238
	Total financial assets not accounted for at fair value	$	2,658			$	2,656		$	1,639		$	—		$	1,017
	Financial liabilities:
	Annuity benefits accumulated (*)	$	20,741			$	19,959		$	—		$	—		$	19,959
	Long-term debt	913				985			—			909			76
	Total financial liabilities not accounted for at fair value	$	21,654			$	20,944		$	—		$	909		$	20,035
	(*)	Excludes life contingent annuities in the payout phase.

Investments_Tables

Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Available for sale fixed maturities and equity securities	Available for sale fixed maturities and equity securities at December 31 consisted of the following (in millions):
		2014													2013
		Amortized				Fair			Gross Unrealized						Amortized			Fair			Gross Unrealized
		Cost				Value			Gains			Losses			Cost			Value			Gains			Losses
	Fixed maturities:
	U.S. Government and government agencies	$	347			$	353		$	8		$	(2	)	$	310		$	314		$	7		$	(3	)
	States, municipalities and political subdivisions	6,393				6,747			364			(10		)	5,360			5,372			156			(144		)
	Foreign government	184				194			10			—			198			208			10			—
	Residential MBS	4,046				4,442			411			(15		)	3,947			4,310			391			(28		)
	Commercial MBS	2,294				2,451			158			(1		)	2,535			2,724			192			(3		)
	Asset-backed securities	3,872				3,887			37			(22		)	2,477			2,493			35			(19		)
	Corporate and other	11,938				12,660			751			(29		)	10,539			11,035			604			(108		)
	Total fixed maturities	$	29,074			$	30,734		$	1,739		$	(79	)	$	25,366		$	26,456		$	1,395		$	(305	)
	Common stocks	$	885			$	1,087		$	227		$	(25	)	$	665		$	858		$	209		$	(16	)
	Perpetual preferred stocks	$	398			$	414		$	21		$	(5	)	$	266		$	265		$	9		$	(10	)
Available for sale securities in a continuous unrealized loss position	The following tables show gross unrealized losses (dollars in millions) on fixed maturities and equity securities by investment category and length of time that individual securities have been in a continuous unrealized loss position at December 31, 2014 and 2013.
			Less Than Twelve Months									Twelve Months or More
			Unrealized				Fair			Fair Value as		Unrealized			Fair			Fair Value as
			Loss				Value			% of Cost		Loss			Value			% of Cost
		2014
		Fixed maturities:
		U.S. Government and government agencies	$	—			$	39		100	%	$	(2	)	$	15		88	%
		States, municipalities and political subdivisions	(2		)		222			99	%	(8		)	408			98	%
		Residential MBS	(4		)		298			99	%	(11		)	209			95	%
		Commercial MBS	(1		)		38			97	%	—			11			100	%
		Asset-backed securities	(11		)		1,389			99	%	(11		)	622			98	%
		Corporate and other	(16		)		588			97	%	(13		)	433			97	%
		Total fixed maturities	$	(34	)		$	2,574		99	%	$	(45	)	$	1,698		97	%
		Common stocks	$	(25	)		$	260		91	%	$	—		$	—		—	%
		Perpetual preferred stocks	$	(1	)		$	45		98	%	$	(4	)	$	55		93	%
		2013
		Fixed maturities:
		U.S. Government and government agencies	$	(3	)		$	60		95	%	$	—		$	—		—	%
		States, municipalities and political subdivisions	(135		)		2,219			94	%	(9		)	73			89	%
		Residential MBS	(9		)		553			98	%	(19		)	212			92	%
		Commercial MBS	(3		)		106			97	%	—			2			100	%
		Asset-backed securities	(18		)		1,310			99	%	(1		)	28			97	%
		Corporate and other	(101		)		2,634			96	%	(7		)	85			92	%
		Total fixed maturities	$	(269	)		$	6,882		96	%	$	(36	)	$	400		92	%
		Common stocks	$	(16	)		$	158		91	%	$	—		$	—		—	%
		Perpetual preferred stocks	$	(6	)		$	91		94	%	$	(4	)	$	20		83	%
Roll forward of cumulative credit portion of other-than-temporary impairments on fixed maturity securities	A progression of the credit portion of other-than-temporary impairments on fixed maturity securities for which the non-credit portion of an impairment has been recognized in other comprehensive income is shown below (in millions):
		2014				2013			2012
	Balance at January 1	$	194			$	192		$	187
	Additional credit impairments on:
	Previously impaired securities	—				—			5
	Securities without prior impairments	—				3			2
	Reductions due to sales or redemptions	(24		)		(1		)	(2		)
	Balance at December 31	$	170			$	194		$	192
Available for sale fixed maturity securities by contractual maturity date	The table below sets forth the scheduled maturities of available for sale fixed maturities as of December 31, 2014 (dollars in millions). Securities with sinking funds are reported at average maturity. Actual maturities may differ from contractual maturities because certain securities may be called or prepaid by the issuers.
		Amortized				Fair Value
		Cost				Amount			%
	Maturity
	One year or less	$	888			$	906		3	%
	After one year through five years	4,803				5,142			17	%
	After five years through ten years	8,797				9,211			30	%
	After ten years	4,374				4,695			15	%
		18,862				19,954			65	%
	ABS (average life of approximately 4-1/2 years)	3,872				3,887			13	%
	MBS (average life of approximately 4-1/2 years)	6,340				6,893			22	%
	Total	$	29,074			$	30,734		100	%
Components of the net unrealized gain on securities, included in Accumulated Other Comprehensive Income	The following table shows (in millions) the components of the net unrealized gain on securities that is included in AOCI in AFG’s Balance Sheet.
		Pretax				Deferred Tax and			Net
						Amounts  Attributable
						to Noncontrolling
						Interests
	31-Dec-14
	Unrealized gain on:
	Fixed maturities — annuity segment (*)	$	1,157			$	(405	)	$	752
	Fixed maturities — all other	503				(185		)	318
	Equity securities	218				(79		)	139
	Deferred policy acquisition costs — annuity segment	(531		)		186			(345		)
	Annuity benefits accumulated	(112		)		39			(73		)
	Life, accident and health reserves	(104		)		36			(68		)
	Unearned revenue	31				(11		)	20
		$	1,162			$	(419	)	$	743
	31-Dec-13
	Unrealized gain on:
	Fixed maturities — annuity segment (*)	$	729			$	(255	)	$	474
	Fixed maturities — all other	361				(133		)	228
	Equity securities	192				(70		)	122
	Deferred policy acquisition costs — annuity segment	(345		)		121			(224		)
	Annuity benefits accumulated	(71		)		25			(46		)
	Life, accident and health reserves	(8		)		3			(5		)
	Unearned revenue	22				(8		)	14
		$	880			$	(317	)	$	563
	(*)    Unrealized gains on fixed maturity investments supporting AFG’s annuity benefits accumulated.
Net investment income earned and investment expenses incurred	The following table shows (in millions) investment income earned and investment expenses incurred.
		2014				2013			2012
	Investment income:
	Fixed maturities	$	1,352			$	1,241		$	1,216
	Equity securities	66				50			36
	Equity in earnings of partnerships and similar investments (*)	18				—			—
	Other	77				72			66
	Gross investment income	1,513				1,363			1,318
	Investment expenses	(12		)		(17		)	(17		)
	Net investment income	$	1,501			$	1,346		$	1,301
	(*)	Equity in the earnings of partnerships has not been material and was included in realized gains (losses) on securities prior to 2014.
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments	Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments are summarized as follows (in millions):
		Fixed				Equity			Mortgage			Other (a)			Tax			Noncon-			Total
		Maturities				Securities			Loans						Effects			trolling
									and Other									Interests
									Investments
	Year ended December 31, 2014
	Realized before impairments	$	36			$	53		$	1		$	(2	)	$	(32	)	$	(2	)	$	54
	Realized — impairments	(15		)		(26		)	—			5			13			1			(22		)
	Change in unrealized	570				26			—			(314		)	(99		)	(3		)	180
	Year ended December 31, 2013
	Realized before impairments	$	36			$	196		$	2		$	(1	)	$	(82	)	$	(2	)	$	149
	Realized — impairments	(5		)		(5		)	(5		)	3			4			—			(8		)
	Change in unrealized	(945		)		31			—			504			144			6			(260		)
	Year ended December 31, 2012
	Realized before impairments	$	55			$	192		$	(3	)	$	(8	)	$	(83	)	$	(2	)	$	151
	Realized — impairments	(9		)		(24		)	—			7			9			—			(17		)
	Change in unrealized	790				(23		)	—			(379		)	(136		)	(7		)	245
	(a)	Primarily adjustments to deferred policy acquisition costs and reserves related to annuities and long-term care business.
Gross realized gains and losses on available for sale fixed maturity and equity security investments	Gross realized gains and losses (excluding impairment writedowns and mark-to-market of derivatives) on available for sale fixed maturity and equity security investment transactions included in the Statement of Cash Flows consisted of the following (in millions):
		2014				2013			2012
	Fixed maturities:
	Gross gains	$	36			$	44		$	55
	Gross losses	(2		)		(5		)	(4		)
	Equity securities:
	Gross gains	53				193			196
	Gross losses	—				—			(4		)

Derivatives_Tables

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives included in Balance Sheet at fair value	The following derivatives that do not qualify for hedge accounting under GAAP are included in AFG’s Balance Sheet at fair value (in millions):
				31-Dec-14						31-Dec-13
	Derivative		Balance Sheet Line	Asset			Liability			Asset			Liability
	MBS with embedded derivatives		Fixed maturities	$	158		$	—		$	140		$	—
	Public company warrants		Equity securities	19			—			19			—
	Interest rate swaptions		Other investments	—			—			2			—
	Fixed-indexed annuities (embedded derivative)		Annuity benefits accumulated	—			1,160			—			804
	Equity index call options		Other investments	322			—			272			—
	Reinsurance contracts (embedded derivative)		Other liabilities	—			13			—			10
				$	499		$	1,173		$	433		$	814
Summary of gain (loss) included in the Statement of Earnings for changes in the fair value of derivatives	The following table summarizes the gain (loss) included in the Statement of Earnings for changes in the fair value of derivatives that do not qualify for hedge accounting for 2014, 2013 and 2012 (in millions):
	Derivative		Statement of Earnings Line	2014			2013			2012
	MBS with embedded derivatives		Realized gains on securities	$	3		$	(3	)	$	5
	Public company warrants		Realized gains on securities	—			3			—
	Interest rate swaptions		Realized gains on securities	(2		)	1			(4		)
	Fixed-indexed annuities (embedded derivative) (*)		Annuity benefits	(182		)	(182		)	(57		)
	Equity index call options		Annuity benefits	181			210			66
	Reinsurance contracts (embedded derivative)		Net investment income	(3		)	7			(6		)
				$	(3	)	$	36		$	4
	(*)	The change in fair value of the embedded derivative includes gains related to unlocking of actuarial assumptions of $58 million in 2014, $2 million in 2013 and $36 million in 2012.

Deferred_Policy_Acquisition_Co1

Deferred Policy Acquisition Costs (Tables)	12 Months Ended
	Dec. 31, 2014
Deferred Policy Acquisition Costs Disclosures [Abstract]
Deferred Policy Acquisition Costs Details	A progression of deferred policy acquisition costs is presented below (in millions):
		P&C			Annuity and Other (*)
		Deferred			Deferred			Sales												Consolidated
		Costs			Costs			Inducements			PVFP			Unrealized			Total			Total
	Balance at December 31, 2011	$	189		$	916		$	189		$	144		$	(537	)	$	712		$	901
	Additions	438			212			15			—			—			227			665
	Amortization:
	Periodic amortization	(423		)	(148		)	(30		)	(17		)	—			(195		)	(618		)
	Annuity unlocking	—			(33		)	(4		)	—			—			(37		)	(37		)
	Loss recognition charge	—			(67		)	—			(12		)	—			(79		)	(79		)
	Included in realized gains	—			(1		)	—			—			—			(1		)	(1		)
	Sale of subsidiaries	—			(92		)	—			(16		)	—			(108		)	(108		)
	Change in unrealized	—			—			—			—			(173		)	(173		)	(173		)
	Balance at December 31, 2012	204			787			170			99			(710		)	346			550
	Additions	468			222			11			—			—			233			701
	Amortization:
	Periodic amortization	(460		)	(140		)	(30		)	(14		)	—			(184		)	(644		)
	Annuity unlocking	—			4			(2		)	—			—			2			2
	Included in realized gains	—			2			—			—			—			2			2
	Foreign currency translation	(1		)	—			—			—			—			—			(1		)
	Change in unrealized	—			—			—			—			365			365			365
	Balance at December 31, 2013	211			875			149			85			(345		)	764			975
	Additions	497			198			8			—			—			206			703
	Amortization:
	Periodic amortization	(485		)	(130		)	(26		)	(11		)	—			(167		)	(652		)
	Annuity unlocking	—			(20		)	—			—			—			(20		)	(20		)
	Included in realized gains	—			2			1			—			—			3			3
	Foreign currency translation	(2		)	—			—			—			—			—			(2		)
	Change in unrealized	—			—			—			—			(186		)	(186		)	(186		)
	Balance at December 31, 2014	$	221		$	925		$	132		$	74		$	(531	)	$	600		$	821
	(*)	Includes AFG’s run-off long-term care and life segment and Medicare supplement and critical illness segment (sold in August 2012).

Managed_Investment_Entities_Ta

Managed Investment Entities (Tables)	12 Months Ended
	Dec. 31, 2014
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]
Selected financial information related to collateralized loan obligations	Selected financial information related to the CLOs is shown below (in millions):
		Year ended December 31,
		2014			2013			2012
	Gains (losses) on change in fair value of assets/liabilities (a):
	Assets	$	(66	)	$	11		$	95
	Liabilities	22			(25		)	(189		)
	Management fees paid to AFG	25			16			18
	CLO earnings (losses) attributable to (b):
	AFG shareholders	16			35			31
	Noncontrolling interests	(51		)	(26		)	(98		)
	(a)	Included in Revenues in AFG’s Statement of Earnings.
	(b)	Included in Earnings before income taxes in AFG’s Statement of Earnings.

Goodwill_and_Other_Intangibles1

Goodwill and Other Intangibles (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in the carrying value of goodwill by reporting segment	Changes in the carrying value of goodwill during 2012, 2013 and 2014, by reporting segment, are presented in the following table (in millions):
		Property and		Annuity			Total
		Casualty
	Balance at January 1, 2012	$	152	$	34		$	186
	Sale of subsidiary in 2012	—		(1		)	(1		)
	Balance at December 31, 2012 and 2013	152		33			185
	Acquisition of subsidiary in 2014	16		—			16
	Balance at December 31, 2014	$	168	$	33		$	201

LongTerm_Debt_Tables

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Schedule of long-term debt instruments	The carrying value of long-term debt consisted of the following at December 31 (in millions):
		2014		2013
	Direct Senior Obligations of AFG:
	9-7/8% Senior Notes due June 2019	$	350	$	350
	6-3/8% Senior Notes due June 2042	230		230
	5-3/4% Senior Notes due August 2042	125		125
	7% Senior Notes due September 2050	132		132
	Other	3		3
		840		840
	Direct Subordinated Obligations of AFG:
	6-1/4% Subordinated Debentures due September 2054	150		—
	Subsidiaries:
	Notes payable secured by real estate due 2015 through 2016	59		61
	National Interstate bank credit facility	12		12
		71		73
		$	1,061	$	913
Summary of secured and unsecured long-term debt	As shown below at December 31 (in millions), the majority of AFG’s long-term debt is unsecured obligations of the holding company and its subsidiaries.
		2014		2013
	Senior unsecured obligations	$	852	$	852
	Subordinated unsecured obligations	150		—
	Obligations secured by real estate	59		61
		$	1,061	$	913

Shareholders_Equity_Tables

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Summary of stock options activity	Data for stock options issued under AFG’s stock incentive plans is presented below:
		Shares			Average				Average		Aggregate
					Exercise				Remaining		Intrinsic
					Price				Contractual		Value
									Term		(in millions)
	Outstanding at January 1, 2014	6,608,614			$	32.16
	Granted	1,047,375			$	56.47
	Exercised	(1,262,313	)		$	28.19
	Forfeited/Cancelled	(9,877	)		$	42.22
	Outstanding at December 31, 2014	6,383,799			$	36.92			5.8 years		$	152
	Options exercisable at December 31, 2014	3,465,644			$	30.04			4.1 years		$	106
Assumptions used in estimating weighted average fair value of options on grant date
		2014				2013				2012
	Exercise price	$	56.47			$	44.01			$	38.1
	Expected dividend yield	1.6		%		1.8		%		1.8		%
	Expected volatility	26		%		39		%		39		%
	Expected term (in years)	7.25				7.25				7.25
	Risk-free rate	2.2		%		1.36		%		1.4		%
	Grant date fair value	$	14.66			$	15.1			$	13.02
Summary of restricted stock awards activity	The restricted Common Stock that AFG has granted generally vests over a three or four year period. Data relating to grants of restricted stock is presented below:
		Shares			Average
					Grant Date
					Fair Value
	Outstanding at January 1, 2014	552,569			$	37.79
	Granted	102,330			$	56.44
	Vested	(139,449	)		$	31.05
	Outstanding at December 31, 2014	515,450			$	43.32
Components of accumulated other comprehensive income (loss)	The progression of the components of accumulated other comprehensive income follows (in millions):
						Other Comprehensive Income
		AOCI				Pretax				Tax			Net			Attributable to			Attributable to			Other (c)			AOCI
		Beginning											of			noncontrolling			shareholders						Ending
		Balance											tax			interests									Balance
	Year ended December 31, 2014
	Net unrealized gains on securities:
	Unrealized holding gains (losses) on securities arising during the period					$	334			$	(118	)	$	216		$	(4	)	$	212
	Reclassification adjustment for realized (gains) losses included in net earnings (a)					(52		)		19			(33		)	1			(32		)
	Total net unrealized gains on securities (b)	$	563			282				(99		)	183			(3		)	180			$	—		$	743
	Foreign currency translation adjustments	1				(9		)		—			(9		)	—			(9		)	—			(8		)
	Pension and other postretirement plans adjustments	(4		)		(6		)		2			(4		)	—			(4		)	—			(8		)
	Total	$	560			$	267			$	(97	)	$	170		$	(3	)	$	167		$	—		$	727
	Year ended December 31, 2013
	Net unrealized gains on securities:
	Unrealized holding gains (losses) on securities arising during the period					$	(188	)		$	66		$	(122	)	$	4		$	(118	)
	Reclassification adjustment for realized (gains) losses included in net earnings (a)					(222		)		78			(144		)	2			(142		)
	Total net unrealized gains on securities (b)	$	823			(410		)		144			(266		)	6			(260		)	$	—		$	563
	Foreign currency translation adjustments	14				(13		)		—			(13		)	—			(13		)	—			1
	Pension and other postretirement plans adjustments	(6		)		3				(1		)	2			—			2			—			(4		)
	Total	$	831			$	(420	)		$	143		$	(277	)	$	6		$	(271	)	$	—		$	560
	Year ended December 31, 2012
	Net unrealized gains on securities (b)	$	578			$	388			$	(136	)	$	252		$	(7	)	$	245		$	—		$	823
	Foreign currency translation adjustments	10				6				—			6			(1		)	5			(1		)	14
	Pension and other postretirement plans adjustments	(8		)		2				—			2			—			2			—			(6		)
	Total	$	580			$	396			$	(136	)	$	260		$	(8	)	$	252		$	(1	)	$	831
	(a)	The reclassification adjustment out of net unrealized gains on securities affected the following lines in AFG’s Consolidated Statement of Earnings:
		OCI component		Affected line in the Consolidated Statement of Earnings
		Pretax		Realized gains on securities
		Tax		Provision for income taxes
		Attributable to noncontrolling interests		Net earnings (loss) attributable to noncontrolling interests
	(b)	Includes net unrealized gains of $58 million at December 31, 2014 compared to net unrealized gains of $54 million and $33 million at December 31, 2013 and 2012, related to securities for which only the credit portion of an other-than-temporary impairment has been recorded in earnings.
	(c)	Other relates to the 2012 acquisition of noncontrolling interest in a subsidiary.

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Reconciliation of income taxes at the statutory rate and income taxes shown in the Statement of Earnings	The following is a reconciliation of income taxes at the statutory rate of 35% to the provision for income taxes as shown in the Statement of Earnings (dollars in millions):
		2014							2013						2012
		Amount				% of EBT			Amount				% of EBT		Amount			% of EBT
	Earnings before income taxes (“EBT”)	$	626						$	689					$	537
	Income taxes at statutory rate	$	219			35	%		$	241			35	%	$	188		35	%
	Effect of:
	Tax exempt interest	(25		)		(4	%)		(21		)		(3	%)	(23		)	(4	%)
	Losses of managed investment entities	18				3	%		9				1	%	34			6	%
	Change in valuation allowance	7				1	%		1				—	%	3			1	%
	Subsidiaries not in AFG’s tax return	1				—	%		2				—	%	(1		)	—	%
	Tax case and settlement of open tax years	—				—	%		—				—	%	(67		)	(13	%)
	Other	—				—	%		4				1	%	1			—	%
	Provision for income taxes as shown in the Statement of Earnings	$	220			35	%		$	236			34	%	$	135		25	%
Components of income tax provision (credit)	The total income tax provision (credit) consists of (in millions):
		2014				2013				2012
	Current taxes:
	Federal	$	265			$	308			$	146
	State	8				5				6
	Deferred taxes:
	Federal	(53		)		(77		)		(17		)
	Provision for income taxes	$	220			$	236			$	135
Summary of operating loss carryforwards	For income tax purposes, AFG and its subsidiaries had the following carryforwards available at December 31, 2014 (in millions):
		Expiring		Amount
	Operating Loss – U.S.	2017 - 2024		$	144
	Operating Loss – United Kingdom	indefinite		131			(*)
	(*)	£85 million
Components of deferred tax assets and liabilities	Deferred income tax assets and liabilities reflect temporary differences between the carrying amounts of assets and liabilities recognized for financial reporting purposes and the amounts recognized for tax purposes. The significant components of deferred tax assets and liabilities included in the Balance Sheet at December 31 were as follows (in millions):
		2014				2013
	Deferred tax assets:
	Federal net operating loss carryforwards	$	51			$	51
	Foreign underwriting losses	56				50
	Insurance claims and reserves	746				558
	Employee benefits	107				98
	Other, net	26				51
	Total deferred tax assets before valuation allowance	986				808
	Valuation allowance against deferred tax assets	(109		)		(103		)
	Total deferred tax assets	877				705
	Deferred tax liabilities:
	Subsidiaries not in AFG’s tax return (*)	(61		)		(60		)
	Investment securities	(663		)		(443		)
	Deferred policy acquisition costs	(178		)		(234		)
	Total deferred tax liabilities	(902		)		(737		)
	Net deferred tax liability	$	(25	)		$	(32	)
	(*)    Related to National Interstate Corporation, a 51%-owned subsidiary.
Progression of the liability for uncertain tax positions, excluding interest and penalties	A progression of the liability for uncertain tax positions, excluding interest and penalties, follows (in millions):
		2014				2013				2012
	Balance at January 1	$	19			$	18			$	59
	Reductions for tax positions of prior years	(8		)		—				(46		)
	Additions for tax positions of current year	—				1				5
	Settlements	(11		)		—				—
	Balance at December 31	$	—			$	19			$	18

Quarterly_Operating_Results_Un1

Quarterly Operating Results (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly operating results	The following are quarterly results of consolidated operations for the two years ended December 31, 2014 (in millions, except per share amounts). Quarterly earnings per share do not add to year-to-date amounts due to changes in shares outstanding.
		1st		2nd			3rd			4th			Total
		Quarter		Quarter			Quarter			Quarter			Year
	2014
	Revenues	$	1,211	$	1,392		$	1,581		$	1,529		$	5,713
	Net earnings, including noncontrolling interests	107		83			91			125			406
	Net earnings attributable to shareholders	103		106			116			127			452
	Earnings attributable to shareholders per Common Share:
	Basic	$	1.15	$	1.18		$	1.3		$	1.44		$	5.07
	Diluted	1.13		1.15			1.28			1.41			4.97
	Average number of Common Shares:
	Basic	89.6		89.6			89			87.9			89
	Diluted	91.6		91.6			90.9			89.8			91
	2013
	Revenues	$	1,148	$	1,139		$	1,443		$	1,362		$	5,092
	Net earnings, including noncontrolling interests	113		77			98			165			453
	Net earnings attributable to shareholders	120		110			83			158			471
	Earnings attributable to shareholders per Common Share:
	Basic	$	1.34	$	1.23		$	0.94		$	1.77		$	5.27
	Diluted	1.32		1.2			0.92			1.73			5.16
	Average number of Common Shares:
	Basic	89.4		89.6			89.1			89.4			89.3
	Diluted	91		91.5			91			91.4			91.2
Quarterly information on realized gains (losses) and favorable (unfavorable) development on unpaid loss and loss adjustment expenses	Pretax realized gains on subsidiaries and securities (including other-than-temporary impairments) and favorable (adverse) prior year development of AFG’s liability for losses and loss adjustment expenses (“LAE”) were as follows (in millions):
		1st		2nd			3rd			4th			Total
		Quarter		Quarter			Quarter			Quarter			Year
	Realized Gains
	2014	$	19	$	12		$	13		$	8		$	52
	2013	57		41			56			63			217
	Prior Year Development Favorable (Adverse)
	2014	$	31	$	(14	)	$	(13	)	$	(10	)	$	(6	)
	2013	28		22			(40		)	5			15

Insurance_Tables

Insurance (Tables)	12 Months Ended
	Dec. 31, 2014
Insurance [Abstract]
Reconciliation of beginning and ending liability for unpaid losses and loss adjustment expenses	The following table provides an analysis of changes in the liability for losses and loss adjustment expenses, net of reinsurance (and grossed up), over the past three years (in millions):
		2014			2013			2012
	Balance at beginning of period	$	4,288		$	4,129		$	4,282
	Provision for losses and LAE occurring in the current year	2,488			2,055			1,903
	Net increase (decrease) in provision for claims of prior years	6			(15		)	(30		)
	Total losses and LAE incurred	2,494			2,040			1,873
	Payments for losses and LAE of:
	Current year	(789		)	(739		)	(841		)
	Prior years	(1,340		)	(1,131		)	(1,185		)
	Total payments	(2,129		)	(1,870		)	(2,026		)
	Reserves of businesses acquired (*)	1,028			—			—
	Foreign currency translation and other	(36		)	(11		)	—
	Balance at end of period	5,645			4,288			4,129
	Add back reinsurance recoverables, net of allowance	2,227			2,122			2,716
	Gross unpaid losses and LAE included in the Balance Sheet	$	7,872		$	6,410		$	6,845
	(*)   Reflects the acquisition of Summit in April 2014 (see Note B — “Acquisitions and Sales of Businesses”).
Statutory information	Net earnings and capital and surplus on a statutory basis for the insurance subsidiaries were as follows (in millions):
		Net Earnings									Capital and Surplus
		2014			2013			2012			2014		2013
	Property and casualty companies	$	318		$	332		$	221		$	2,286	$	1,896
	Life insurance companies	349			294			171			1,714		1,619
Reinsurance information	The following table shows (in millions) (i) amounts deducted from property and casualty written and earned premiums in connection with reinsurance ceded, (ii) written and earned premiums included in income for reinsurance assumed and (iii) reinsurance recoveries, which represent ceded losses and loss adjustment expenses.
		2014			2013			2012
	Direct premiums written	$	5,387		$	4,744		$	4,283
	Reinsurance assumed	90			61			38
	Reinsurance ceded	(1,457		)	(1,464		)	(1,372		)
	Net written premiums	$	4,020		$	3,341		$	2,949
	Direct premiums earned	$	5,195		$	4,684		$	4,120
	Reinsurance assumed	75			45			36
	Reinsurance ceded	(1,392		)	(1,525		)	(1,309		)
	Net earned premiums	$	3,878		$	3,204		$	2,847
	Reinsurance recoveries	$	895		$	1,255		$	1,743
Schedule of reserve liabilities for annuity benefits accumulated	For certain products, the liability for “annuity benefits accumulated” includes reserves for excess benefits expected to be paid on future deaths and annuitizations (“EDAR”), guaranteed withdrawal benefits and accrued persistency and premium bonuses. The liabilities included in AFG’s Balance Sheet for these benefits, excluding the impact of unrealized gains on securities, were as follows at December 31 (in millions):
		2014			2013
	Excess death and annuitization	$	213		$	197
	Guaranteed withdrawal benefits	151			71
	Accrued persistency and premium bonuses	14			15

Accounting_Policies_Details

Accounting Policies (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Variable Interest Entity [Line Items]
Assets	$3,108	$2,888
Liabilities	2,819	2,567
Weighted average common shares adjustment related to stock-based compensation	2	1.9	1.7
Anti-dilutive potential common shares related to stock-based compensation plans	1	1.1	1.8
Maturities of short term investments	3 months
New collateralized loan obligation temporary warehousing entities [Member]
Variable Interest Entity [Line Items]
Assets	17
Liabilities	$12

Acquisitions_and_Sales_of_Busi2

Acquisitions and Sales of Businesses (Details) (USD $)	12 Months Ended			0 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Apr. 01, 2014		Dec. 31, 2011
Business Acquisition [Line Items]
Total purchase price	$267	$0	$0
Allocation of excess purchase price:
Goodwill	201	185	185			186
Summit Holding Southeast, Inc [Member]
Business Acquisition [Line Items]
Total purchase price				259
Tangible assets acquired:
Cash and cash equivalents				1,078
Fixed maturities, available for sale				92
Recoverables from reinsurers				116
Agents’ balances and premiums receivable				41
Deferred tax assets, net				67	[1]
Other receivables				21
Other assets				11
Total tangible assets acquired				1,426
Liabilities acquired:
Unpaid losses and loss adjustment expenses				1,142
Unearned premiums				3
Payable to reinsurers				3
Other liabilities				66
Total liabilities acquired				1,214
Net tangible assets acquired, at fair value				212
Excess purchase price over net tangible assets acquired				47
Allocation of excess purchase price:
Intangible assets acquired				47	[2]
Deferred tax on intangible assets acquired				-16	[1]
Goodwill				$16
[1]	Included with AFG’s net deferred tax liabilities, which are included in Other liabilities in AFG’s Consolidated Balance Sheet.
[2]	Included in Other assets in AFG’s Consolidated Balance Sheet.

Acquisitions_and_Sales_of_Busi3

Acquisitions and Sales of Businesses (Details 1) (Medicare supplement and critical illness businesses [Member], USD $)	1 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Aug. 31, 2012	Dec. 31, 2012
Medicare supplement and critical illness businesses [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale proceeds	$326	$326
Expenses	-11
Net proceeds	315
Assets of businesses sold:
Cash and investments	217
Deferred policy acquisition costs	108
Other assets	31
Total assets	356
Liabilities of businesses sold:
Life, accident and health reserves	209
Other liabilities	2
Total liabilities	211
Net assets of businesses sold	145
Gain on sale of subsidiaries	$170	$170

Acquisitions_and_Sales_of_Busi4

Acquisitions and Sales of Businesses (Details Textual) (USD $)	1 Months Ended	12 Months Ended			0 Months Ended	9 Months Ended	0 Months Ended
In Millions, unless otherwise specified	Aug. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Apr. 01, 2014	Dec. 31, 2014	Mar. 27, 2014	Dec. 31, 2011
	company
Business Acquisition [Line Items]
Payments to acquire business		$267	$0	$0
Weighted average useful life of finite-lived intangible assets acquired		6 years
Goodwill		201	185	185		201		186
Percentage of interest acquired in a subsidiary				28.00%
Purchase of interest not already owned in a subsidiary				17
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of undisclosed insurance companies sold	4
Medicare supplement and critical illness businesses [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale proceeds	326			326
Pretax gain on sale of subsidiaries	170			170
Total revenues				212
Total costs and expenses				184
Earnings before income taxes				28
Small annuity and supplemental insurance company [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale proceeds				7
Summit Holding Southeast, Inc [Member]
Business Acquisition [Line Items]
Payments to acquire business					259
Capital contributions to acquired business					140
Total capital investment in acquired business					399
Net written premiums of acquired business		539
Net earned premiums of acquired business						410
Indefinite-lived intangible assets acquired					1
Finite-lived intangible assets acquired					46
Weighted average useful life of finite-lived intangible assets acquired					7 years
Goodwill					16
Selective Insurance Company of America Self-Insured Pooled Group [Member]
Business Acquisition [Line Items]
Payments to acquire business							8
In-force gross written premiums of acquired book of business							38
Maximum [Member] | Summit Holding Southeast, Inc [Member]
Business Acquisition [Line Items]
Expenses related to the acquisition of business (are less than)					$1

Segments_of_Operations_Details

Segments of Operations (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
In Millions, unless otherwise specified
Segment Reporting Information [Line Items]
Total assets	$47,535		$42,087		$39,171
Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Total assets	14,069	[1]	11,717	[1]	12,163	[1]
Annuity [Member]
Segment Reporting Information [Line Items]
Total assets	27,317		24,294		20,909
Run-off Long-term Care and Life [Member]
Segment Reporting Information [Line Items]
Total assets	2,489		2,408		2,304
Other [Member]
Segment Reporting Information [Line Items]
Total assets	$3,660		$3,668		$3,795
[1]	Not allocable to sub-segments.

Segments_of_Operations_Details1

Segments of Operations (Details 1) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Total premiums earned									$3,878		$3,204		$2,847
Net investment income									1,501		1,346		1,301
Other income									102		97		89
Revenues before realized gains (losses)									5,661		4,875		4,586
Realized gains on securities									52		221		210
Realized gains (losses) on subsidiaries									0		-4		161
Total revenues	1,529	1,581	1,392	1,211	1,362	1,443	1,139	1,148	5,713		5,092		4,957
Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Net investment income									294		263		275
Other income									9		15		24
Revenues before realized gains (losses)									4,181		3,482		3,146
Annuity [Member]
Segment Reporting Information [Line Items]
Net investment income									1,136		1,034		976
Other income									78		67		52
Revenues before realized gains (losses)									1,214		1,101		1,028
Run-off Long-term Care and Life [Member]
Segment Reporting Information [Line Items]
Revenues before realized gains (losses)									194		194		191
Medicare Supplement and Critical Illness [Member]
Segment Reporting Information [Line Items]
Revenues before realized gains (losses)									0	[1]	0	[1]	212	[1]
Other [Member]
Segment Reporting Information [Line Items]
Revenues before realized gains (losses)									72		98		9
Specialty Property and transportation [Member]
Segment Reporting Information [Line Items]
Total premiums earned									1,544		1,521		1,423
Specialty casualty [Member]
Segment Reporting Information [Line Items]
Total premiums earned									1,765		1,135		948
Specialty financial [Member]
Segment Reporting Information [Line Items]
Total premiums earned									469		469		405
Specialty Other [Member]
Segment Reporting Information [Line Items]
Total premiums earned									$100		$79		$71
[1]	Sold in August 2012.

Segments_of_Operations_Details2

Segments of Operations (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	$574		$472		$166
Realized gains on securities	52		221		210
Realized gains (losses) on subsidiaries	0		-4		161
Earnings before income taxes	626		689		537
Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	212		145		87
Investment and other income, net	244		230		235
Earnings before realized gains (losses) and income taxes	456		375		322
Annuity [Member]
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	328	[1]	323	[1]	256	[1]
Run-off Long-term Care and Life [Member]
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	-10	[2]	-10	[2]	-157	[2]
Medicare Supplement and Critical Illness [Member]
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	0	[3]	0	[3]	28	[3]
Other [Member]
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	-200	[4]	-216	[4]	-283	[4]
Specialty Property and transportation [Member]
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	21		12		19
Specialty casualty [Member]
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	136		102		53
Specialty financial [Member]
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	64		67		44
Specialty Other [Member]
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	16		25		15
Other Lines [Member]
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	($25)	[5]	($61)	[5]	($44)	[5]
[1]	Includes a $5 million charge in the second quarter of 2013 to cover expected assessments from state guaranty funds related to insolvency and liquidation of an unaffiliated life insurance company.
[2]	Includes a loss recognition charge of $153 million in the fourth quarter of 2012.
[3]	Sold in August 2012.
[4]	Includes holding company expenses, special charges to increase A&E reserves ($6 million in 2014, $22 million in 2013 and $2 million in 2012) and losses of managed investment entities attributable to noncontrolling interests ($51 million in 2014, $26 million in 2013 and $98 million in 2012). Holding company expenses in 2012 also include an $8 million loss on retirement of debt and a $15 million charge for a labor matter related to AFG’s former railroad operations.
[5]	Includes special charges to increase asbestos and environmental (“A&E”) reserves of $24 million, $54 million and $31 million in 2014, 2013 and 2012, respectively.

Segments_of_Operations_Details3

Segments of Operations (Details Textual) (USD $)	12 Months Ended						3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2013
	segment
Segments of Operations (Textual) [Abstract]
Number of segments	5
Revenue derived from sales of property and casualty insurance outside of the United States	5.00%		5.00%		5.00%
Earnings (losses) of managed investment entities attributable to noncontrolling interests	($51)	[1]	($26)	[1]	($98)	[1]
Run-off Long-term Care and Life [Member]
Segments of Operations (Textual) [Abstract]
Loss recognition charge on closed block of long-term care insurance	0		0				153
Other [Member]
Segments of Operations (Textual) [Abstract]
Special charges to increase asbestos and environmental reserves								6	22	2
Earnings (losses) of managed investment entities attributable to noncontrolling interests	-51		-26		-98
Loss on retirement of debt					-8
Charge for a labor matter related to former operations					15
Other Lines [Member]
Segments of Operations (Textual) [Abstract]
Special charges to increase asbestos and environmental reserves								24	54	31
Insurance-related Assessments [Member] | Annuity [Member]
Segments of Operations (Textual) [Abstract]
Charge for guaranty fund assessments for the insolvency and liquidation of an unaffiliated life insurance company											$5
[1]	Included in Earnings before income taxes in AFG’s Statement of Earnings.

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Assets:
Fixed maturities, Available for sale, Fair Value	$30,734		$26,456
Fixed maturities, Trading, Fair Value	266		305
Assets of managed investment entities (MIE)	3,108		2,888
Variable annuity assets (separate accounts)	662	[1]	665	[1]
Other investments — derivatives	322		274
Total assets accounted for at fair value	36,788		31,767
Liabilities:
Liabilities of managed investment entities	2,819		2,567
Total liabilities accounted for at fair value	3,992		3,381
Annuity benefits accumulated [Member]
Liabilities:
Derivatives included in annuity benefits accumulated and other liabilities	1,160		804
Other liabilities [Member]
Liabilities:
Derivatives included in annuity benefits accumulated and other liabilities	13		10
U.S. Government and government agencies [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	353		314
States, municipalities and political subdivisions [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	6,747		5,372
Foreign government [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	194		208
Residential Mortgage Backed Securities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	4,442		4,310
Commercial Mortgage Backed Securities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	2,451		2,724
Asset-backed Securities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	3,887		2,493
All other corporate [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	12,660		11,035
Fixed maturities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	30,734		26,456
Fixed maturities, Trading, Fair Value	266		305
Equity securities [Member]
Assets:
Equity securities, Fair Value	1,696		1,179
Level 1 [Member]
Assets:
Assets of managed investment entities (MIE)	174		266
Variable annuity assets (separate accounts)	0	[1]	0	[1]
Other investments — derivatives	0		0
Total assets accounted for at fair value	1,692		1,464
Liabilities:
Liabilities of managed investment entities	118		156
Total liabilities accounted for at fair value	118		156
Level 1 [Member] | Annuity benefits accumulated [Member]
Liabilities:
Derivatives included in annuity benefits accumulated and other liabilities	0		0
Level 1 [Member] | Other liabilities [Member]
Liabilities:
Derivatives included in annuity benefits accumulated and other liabilities	0		0
Level 1 [Member] | U.S. Government and government agencies [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	164		147
Level 1 [Member] | States, municipalities and political subdivisions [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	0		0
Level 1 [Member] | Foreign government [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	0		0
Level 1 [Member] | Residential Mortgage Backed Securities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	0		0
Level 1 [Member] | Commercial Mortgage Backed Securities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	0		0
Level 1 [Member] | Asset-backed Securities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	0		0
Level 1 [Member] | All other corporate [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	36		28
Level 1 [Member] | Fixed maturities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	200		175
Fixed maturities, Trading, Fair Value	12		0
Level 1 [Member] | Equity securities [Member]
Assets:
Equity securities, Fair Value	1,306		1,023
Level 2 [Member]
Assets:
Assets of managed investment entities (MIE)	2,903		2,592
Variable annuity assets (separate accounts)	662	[1]	665	[1]
Other investments — derivatives	322		274
Total assets accounted for at fair value	33,741		29,412
Liabilities:
Liabilities of managed investment entities	0		0
Total liabilities accounted for at fair value	13		10
Level 2 [Member] | Annuity benefits accumulated [Member]
Liabilities:
Derivatives included in annuity benefits accumulated and other liabilities	0		0
Level 2 [Member] | Other liabilities [Member]
Liabilities:
Derivatives included in annuity benefits accumulated and other liabilities	13		10
Level 2 [Member] | U.S. Government and government agencies [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	174		152
Level 2 [Member] | States, municipalities and political subdivisions [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	6,647		5,311
Level 2 [Member] | Foreign government [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	194		208
Level 2 [Member] | Residential Mortgage Backed Securities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	4,142		3,994
Level 2 [Member] | Commercial Mortgage Backed Securities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	2,407		2,696
Level 2 [Member] | Asset-backed Securities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	3,661		2,418
Level 2 [Member] | All other corporate [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	12,078		10,672
Level 2 [Member] | Fixed maturities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	29,303		25,451
Fixed maturities, Trading, Fair Value	254		305
Level 2 [Member] | Equity securities [Member]
Assets:
Equity securities, Fair Value	297		125
Level 3 [Member]
Assets:
Assets of managed investment entities (MIE)	31		30
Variable annuity assets (separate accounts)	0	[1]	0	[1]
Other investments — derivatives	0		0
Total assets accounted for at fair value	1,355		891
Liabilities:
Liabilities of managed investment entities	2,701		2,411
Total liabilities accounted for at fair value	3,861		3,215
Level 3 [Member] | Annuity benefits accumulated [Member]
Liabilities:
Derivatives included in annuity benefits accumulated and other liabilities	1,160		804
Level 3 [Member] | Other liabilities [Member]
Liabilities:
Derivatives included in annuity benefits accumulated and other liabilities	0		0
Level 3 [Member] | U.S. Government and government agencies [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	15		15
Level 3 [Member] | States, municipalities and political subdivisions [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	100		61
Level 3 [Member] | Foreign government [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	0		0
Level 3 [Member] | Residential Mortgage Backed Securities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	300		316
Level 3 [Member] | Commercial Mortgage Backed Securities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	44		28
Level 3 [Member] | Asset-backed Securities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	226		75
Level 3 [Member] | All other corporate [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	546		335
Level 3 [Member] | Fixed maturities [Member]
Assets:
Fixed maturities, Available for sale, Fair Value	1,231		830
Fixed maturities, Trading, Fair Value	0		0
Level 3 [Member] | Equity securities [Member]
Assets:
Equity securities, Fair Value	$93		$31
[1]	Variable annuity liabilities equal the fair value of variable annuity assets.

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details 1) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified	stock	stock	stock
Perpetual preferred stocks [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of stocks transferred from Level 2 to Level 1	14	15	2
Fair value of assets transferred from Level 2 to Level 1	$96	$70	$16
Number of stocks transferred from Level 1 to Level 2	13	2	7
Fair value of assets transferred from Level 1 to Level 2	83	10	41
Common stocks [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of stocks transferred from Level 2 to Level 1	0	2	0
Fair value of assets transferred from Level 2 to Level 1	0	35	0
Number of stocks transferred from Level 1 to Level 2	7	0	0
Fair value of assets transferred from Level 1 to Level 2	26	0	0
Redeemable preferred stocks [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of stocks transferred from Level 2 to Level 1	1	3	1
Fair value of assets transferred from Level 2 to Level 1	5	21	2
Number of stocks transferred from Level 1 to Level 2	0	0	0
Fair value of assets transferred from Level 1 to Level 2	$0	$0	$0

Fair_Value_Measurements_Detail2

Fair Value Measurements (Details 2) (Embedded derivatives [Member])	12 Months Ended
	Dec. 31, 2014
Unobservable inputs used by management in determining fair value of embedded derivatives
Risk margin for uncertainty in cash flows	0.52%
Minimum [Member]
Unobservable inputs used by management in determining fair value of embedded derivatives
Adjustment for insurance subsidiary's credit risk	0.40%
Surrenders	4.00%
Partial surrenders	2.00%
Annuitizations	1.00%
Deaths	1.50%
Budgeted option costs	2.25%
Maximum [Member]
Unobservable inputs used by management in determining fair value of embedded derivatives
Adjustment for insurance subsidiary's credit risk	1.75%
Surrenders	16.00%
Partial surrenders	6.00%
Annuitizations	1.50%
Deaths	3.00%
Budgeted option costs	3.50%

Fair_Value_Measurements_Detail3

Fair Value Measurements (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
US Treasury and Government [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	$15	$20	$0
Total realized/unrealized gains (losses) included in Net income	0	-2	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	-3	0
Purchases and issuances	0	0	20
Sales and settlements	0	0	0
Transfer into Level 3	0	0	0
Transfer out of Level 3	0	0	0
Financial assets, Ending Balance	15	15	20
States, municipalities and political subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	61	58	83
Total realized/unrealized gains (losses) included in Net income	-1	-1	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	-2	4
Purchases and issuances	30	10	19
Sales and settlements	0	0	-7
Transfer into Level 3	10	0	8
Transfer out of Level 3	0	-4	-49
Financial assets, Ending Balance	100	61	58
Residential Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	316	371	361
Total realized/unrealized gains (losses) included in Net income	4	5	5
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	3	24	17
Purchases and issuances	13	6	96
Sales and settlements	-31	-53	-45
Transfer into Level 3	111	86	228
Transfer out of Level 3	-116	-123	-291
Financial assets, Ending Balance	300	316	371
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	28	22	19
Total realized/unrealized gains (losses) included in Net income	-1	-1	1
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	-1	2
Purchases and issuances	0	0	0
Sales and settlements	0	0	0
Transfer into Level 3	17	8	0
Transfer out of Level 3	0	0	0
Financial assets, Ending Balance	44	28	22
Asset-backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	75	253	228
Total realized/unrealized gains (losses) included in Net income	3	4	7
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	-2	-3	8
Purchases and issuances	99	12	55
Sales and settlements	-39	-57	-36
Transfer into Level 3	117	11	14
Transfer out of Level 3	-27	-145	-23
Financial assets, Ending Balance	226	75	253
All other corporate [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	335	236	291
Total realized/unrealized gains (losses) included in Net income	2	1	3
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	13	-14	9
Purchases and issuances	102	113	86
Sales and settlements	-73	-17	-35
Transfer into Level 3	172	24	15
Transfer out of Level 3	-5	-8	-133
Financial assets, Ending Balance	546	335	236
Trading fixed maturities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance			1
Total realized/unrealized gains (losses) included in Net income			0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)			0
Purchases and issuances			0
Sales and settlements			0
Transfer into Level 3			0
Transfer out of Level 3			-1
Financial assets, Ending Balance			0
Equity securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	31	37	11
Total realized/unrealized gains (losses) included in Net income	1	-1	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	2	6	2
Purchases and issuances	62	53	30
Sales and settlements	-9	-12	0
Transfer into Level 3	22	0	13
Transfer out of Level 3	-16	-52	-19
Financial assets, Ending Balance	93	31	37
Assets of Managed Investment Entities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial assets, Beginning Balance	30	40	44
Total realized/unrealized gains (losses) included in Net income	-3	-5	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0	0	0
Purchases and issuances	6	8	20
Sales and settlements	-2	-7	-14
Transfer into Level 3	0	0	13
Transfer out of Level 3	0	-6	-23
Financial assets, Ending Balance	$31	$30	$40

Fair_Value_Measurements_Detail4

Fair Value Measurements (Details 4) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Liabilities of Managed Investment Entities [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial liabilities, Beginning Balance	($2,411)		($2,745)		($2,593)
Total realized/unrealized gains (losses) included in Net income	22	[1]	-25	[2]	-189	[3]
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0		0		0
Purchases and issuances	-817		-728		-793
Sales and settlements	505		1,068		830
Transfers into Level 3	0		0		0
Transfers out of Level 3	0		19		0
Financial liabilities, Ending Balance	-2,701		-2,411		-2,745
Embedded derivatives [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial liabilities, Beginning Balance	-804		-465		-361
Total realized/unrealized gains (losses) included in Net income	-182	[4]	-182	[5]	-57	[6]
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0		0		0
Purchases and issuances	-221		-192		-73
Sales and settlements	47		35		26
Transfers into Level 3	0		0		0
Transfers out of Level 3	0		0		0
Financial liabilities, Ending Balance	($1,160)		($804)		($465)
[1]	Total realized/unrealized gains (losses) included in net income includes gains of $50 million related to liabilities outstanding as of December 31, 2014. See Note H — “Managed Investment Entities.”
[2]	Total realized/unrealized gains (losses) included in net income includes gains of $7 million related to liabilities outstanding as of December 31, 2013. See Note H — “Managed Investment Entities.”
[3]	Total realized/unrealized gains (losses) included in net income includes losses of $125 million related to liabilities outstanding as of December 31, 2012. See Note H — “Managed Investment Entities.”
[4]	Total realized/unrealized gains (losses) included in net income for the embedded derivatives reflects gains related to the unlocking of actuarial assumptions of $58 million in 2014.
[5]	Total realized/unrealized gains (losses) included in net income for the embedded derivatives reflects gains related to the unlocking of actuarial assumptions of $2 million in 2013.
[6]	Total realized/unrealized gains (losses) included in net income for the embedded derivatives reflects gains related to the unlocking of actuarial assumptions of $36 million in 2012.

Fair_Value_Measurements_Detail5

Fair Value Measurements (Details 5) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Financial assets:
Cash and cash equivalents	$1,343		$1,639		$1,705	$1,324
Mortgage loans	1,117		781
Policy loans	228		238
Financial liabilities:
Long-term debt	1,061		913
Level 1 [Member]
Financial assets:
Cash and cash equivalents	1,343		1,639
Mortgage loans	0		0
Policy loans	0		0
Total financial assets not accounted for at fair value	1,343		1,639
Financial liabilities:
Annuity benefits accumulated	0	[1]	0	[1]
Long-term debt	0		0
Total financial liabilities not accounted for at fair value	0		0
Level 2 [Member]
Financial assets:
Cash and cash equivalents	0		0
Mortgage loans	0		0
Policy loans	0		0
Total financial assets not accounted for at fair value	0		0
Financial liabilities:
Annuity benefits accumulated	0	[1]	0	[1]
Long-term debt	1,106		909
Total financial liabilities not accounted for at fair value	1,106		909
Level 3 [Member]
Financial assets:
Cash and cash equivalents	0		0
Mortgage loans	1,124		779
Policy loans	228		238
Total financial assets not accounted for at fair value	1,352		1,017
Financial liabilities:
Annuity benefits accumulated	23,187	[1]	19,959	[1]
Long-term debt	74		76
Total financial liabilities not accounted for at fair value	23,261		20,035
Carrying Value [Member]
Financial assets:
Cash and cash equivalents	1,343		1,639
Mortgage loans	1,117		781
Policy loans	228		238
Total financial assets not accounted for at fair value	2,688		2,658
Financial liabilities:
Annuity benefits accumulated	23,561	[1]	20,741	[1]
Long-term debt	1,061		913
Total financial liabilities not accounted for at fair value	24,622		21,654
Fair Value [Member]
Financial assets:
Cash and cash equivalents	1,343		1,639
Mortgage loans	1,124		779
Policy loans	228		238
Total financial assets not accounted for at fair value	2,695		2,656
Financial liabilities:
Annuity benefits accumulated	23,187	[1]	19,959	[1]
Long-term debt	1,180		985
Total financial liabilities not accounted for at fair value	$24,367		$20,944
[1]	Excludes life contingent annuities in the payout phase.

Fair_Value_Measurements_Detail6

Fair Value Measurements (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	professional
Fair Value Measurements (Textual) [Abstract]
AFG's internal investment professionals	20
Level 3 assets as a percentage of total assets measured at fair value	3.50%
Percentage of level 3 assets that were priced using non-binding broker quotes	79.00%
Level 3 assets that were priced using non-binding broker quotes	$1,070,000,000
Total realized/unrealized gains (losses) included in net income on liabilities still outstanding	50,000,000	7,000,000	-125,000,000
Maximum [Member]
Fair Value Measurements (Textual) [Abstract]
Percentage of internally developed Level 3 asset fair values to total assets (are less than)	1.00%
Percentage of internally developed Level 3 asset fair values to Shareholders' equity (are less than)	5.00%
Fixed-indexed annuities (embedded derivative) [Member]
Fair Value Measurements (Textual) [Abstract]
Fair value of derivatives in annuity benefits accumulated measured using a discounted cash flow approach	1,160,000,000
Fixed-indexed annuities (embedded derivative) [Member] | Minimum [Member]
Fair Value Measurements (Textual) [Abstract]
Unobservable input surrenders used in Level 3 fair value determination	4.00%
Fixed-indexed annuities (embedded derivative) [Member] | Maximum [Member]
Fair Value Measurements (Textual) [Abstract]
Unobservable input surrenders used in Level 3 fair value determination	16.00%
Fixed-indexed annuities (embedded derivative), majority of future years [Member] | Minimum [Member]
Fair Value Measurements (Textual) [Abstract]
Unobservable input surrenders used in Level 3 fair value determination	5.00%
Fixed-indexed annuities (embedded derivative), majority of future years [Member] | Maximum [Member]
Fair Value Measurements (Textual) [Abstract]
Unobservable input surrenders used in Level 3 fair value determination	11.00%
Not Designated as Hedging Instrument [Member] | Annuity benefits [Member] | Fixed-indexed annuities (embedded derivative) [Member]
Fair Value Measurements (Textual) [Abstract]
Total realized/unrealized gains (losses) included in net income for the embedded derivatives related to the unlocking of actuarial assumptions	$58,000,000	$2,000,000	$36,000,000

Investments_Details

Investments (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Available for sale fixed maturities and equity securities
Fixed maturities, Available for sale, Amortized Cost	$29,074	$25,366
Fixed maturities, Available for sale, Fair Value	30,734	26,456
Equity securities, Available for sale, Amortized Cost	1,283	931
Equity securities, Available for sale, Fair Value	1,501	1,123
U.S. Government and government agencies [Member]
Available for sale fixed maturities and equity securities
Fixed maturities, Available for sale, Amortized Cost	347	310
Fixed maturities, Available for sale, Fair Value	353	314
Fixed maturities, Available for sale, Gross Unrealized, Gains	8	7
Fixed maturities, Available for sale, Gross Unrealized, Losses	-2	-3
States, municipalities and political subdivisions [Member]
Available for sale fixed maturities and equity securities
Fixed maturities, Available for sale, Amortized Cost	6,393	5,360
Fixed maturities, Available for sale, Fair Value	6,747	5,372
Fixed maturities, Available for sale, Gross Unrealized, Gains	364	156
Fixed maturities, Available for sale, Gross Unrealized, Losses	-10	-144
Foreign government [Member]
Available for sale fixed maturities and equity securities
Fixed maturities, Available for sale, Amortized Cost	184	198
Fixed maturities, Available for sale, Fair Value	194	208
Fixed maturities, Available for sale, Gross Unrealized, Gains	10	10
Fixed maturities, Available for sale, Gross Unrealized, Losses	0	0
Residential Mortgage Backed Securities [Member]
Available for sale fixed maturities and equity securities
Fixed maturities, Available for sale, Amortized Cost	4,046	3,947
Fixed maturities, Available for sale, Fair Value	4,442	4,310
Fixed maturities, Available for sale, Gross Unrealized, Gains	411	391
Fixed maturities, Available for sale, Gross Unrealized, Losses	-15	-28
Commercial Mortgage Backed Securities [Member]
Available for sale fixed maturities and equity securities
Fixed maturities, Available for sale, Amortized Cost	2,294	2,535
Fixed maturities, Available for sale, Fair Value	2,451	2,724
Fixed maturities, Available for sale, Gross Unrealized, Gains	158	192
Fixed maturities, Available for sale, Gross Unrealized, Losses	-1	-3
Asset-backed Securities [Member]
Available for sale fixed maturities and equity securities
Fixed maturities, Available for sale, Amortized Cost	3,872	2,477
Fixed maturities, Available for sale, Fair Value	3,887	2,493
Fixed maturities, Available for sale, Gross Unrealized, Gains	37	35
Fixed maturities, Available for sale, Gross Unrealized, Losses	-22	-19
All other corporate [Member]
Available for sale fixed maturities and equity securities
Fixed maturities, Available for sale, Amortized Cost	11,938	10,539
Fixed maturities, Available for sale, Fair Value	12,660	11,035
Fixed maturities, Available for sale, Gross Unrealized, Gains	751	604
Fixed maturities, Available for sale, Gross Unrealized, Losses	-29	-108
Fixed maturities [Member]
Available for sale fixed maturities and equity securities
Fixed maturities, Available for sale, Amortized Cost	29,074	25,366
Fixed maturities, Available for sale, Fair Value	30,734	26,456
Fixed maturities, Available for sale, Gross Unrealized, Gains	1,739	1,395
Fixed maturities, Available for sale, Gross Unrealized, Losses	-79	-305
Common stocks [Member]
Available for sale fixed maturities and equity securities
Equity securities, Available for sale, Amortized Cost	885	665
Equity securities, Available for sale, Fair Value	1,087	858
Equity securities, Available for sale, Gross Unrealized, Gains	227	209
Equity securities, Available for sale, Gross Unrealized, Losses	-25	-16
Perpetual preferred stocks [Member]
Available for sale fixed maturities and equity securities
Equity securities, Available for sale, Amortized Cost	398	266
Equity securities, Available for sale, Fair Value	414	265
Equity securities, Available for sale, Gross Unrealized, Gains	21	9
Equity securities, Available for sale, Gross Unrealized, Losses	($5)	($10)

Investments_Details_1

Investments (Details 1) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
U.S. Government and government agencies [Member]
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	$0	($3)
Fair Value - Less than twelve months	39	60
Fair Value as % of Cost - Less than twelve months	100.00%	95.00%
Unrealized Loss - Twelve months or more	-2	0
Fair Value - Twelve months or more	15	0
Fair Value as % of Cost - Twelve months or more	88.00%	0.00%
States, municipalities and political subdivisions [Member]
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	-2	-135
Fair Value - Less than twelve months	222	2,219
Fair Value as % of Cost - Less than twelve months	99.00%	94.00%
Unrealized Loss - Twelve months or more	-8	-9
Fair Value - Twelve months or more	408	73
Fair Value as % of Cost - Twelve months or more	98.00%	89.00%
Residential Mortgage Backed Securities [Member]
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	-4	-9
Fair Value - Less than twelve months	298	553
Fair Value as % of Cost - Less than twelve months	99.00%	98.00%
Unrealized Loss - Twelve months or more	-11	-19
Fair Value - Twelve months or more	209	212
Fair Value as % of Cost - Twelve months or more	95.00%	92.00%
Commercial Mortgage Backed Securities [Member]
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	-1	-3
Fair Value - Less than twelve months	38	106
Fair Value as % of Cost - Less than twelve months	97.00%	97.00%
Unrealized Loss - Twelve months or more	0	0
Fair Value - Twelve months or more	11	2
Fair Value as % of Cost - Twelve months or more	100.00%	100.00%
Asset-backed Securities [Member]
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	-11	-18
Fair Value - Less than twelve months	1,389	1,310
Fair Value as % of Cost - Less than twelve months	99.00%	99.00%
Unrealized Loss - Twelve months or more	-11	-1
Fair Value - Twelve months or more	622	28
Fair Value as % of Cost - Twelve months or more	98.00%	97.00%
All other corporate [Member]
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	-16	-101
Fair Value - Less than twelve months	588	2,634
Fair Value as % of Cost - Less than twelve months	97.00%	96.00%
Unrealized Loss - Twelve months or more	-13	-7
Fair Value - Twelve months or more	433	85
Fair Value as % of Cost - Twelve months or more	97.00%	92.00%
Fixed maturities [Member]
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	-34	-269
Fair Value - Less than twelve months	2,574	6,882
Fair Value as % of Cost - Less than twelve months	99.00%	96.00%
Unrealized Loss - Twelve months or more	-45	-36
Fair Value - Twelve months or more	1,698	400
Fair Value as % of Cost - Twelve months or more	97.00%	92.00%
Common stocks [Member]
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	-25	-16
Fair Value - Less than twelve months	260	158
Fair Value as % of Cost - Less than twelve months	91.00%	91.00%
Unrealized Loss - Twelve months or more	0	0
Fair Value - Twelve months or more	0	0
Fair Value as % of Cost - Twelve months or more	0.00%	0.00%
Perpetual preferred stocks [Member]
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	-1	-6
Fair Value - Less than twelve months	45	91
Fair Value as % of Cost - Less than twelve months	98.00%	94.00%
Unrealized Loss - Twelve months or more	-4	-4
Fair Value - Twelve months or more	$55	$20
Fair Value as % of Cost - Twelve months or more	93.00%	83.00%

Investments_Details_2

Investments (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Beginning Balance	$194	$192	$187
Additional credit impairments on:
Previously impaired securities	0	0	5
Securities without prior impairments	0	3	2
Reductions due to sales or redemptions	-24	-1	-2
Ending Balance	$170	$194	$192

Investments_Details_3

Investments (Details 3) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
The scheduled maturities of available for sale fixed maturities
Fixed maturities amortized cost, One year or less	$888
Fixed maturities fair value, One year or less	906
Fixed maturities fair value, One year or less, Percent	3.00%
Fixed maturities amortized cost, After one year through five years	4,803
Fixed maturities fair value, After one year through five years	5,142
Fixed maturities fair value, After one year through five years, Percent	17.00%
Fixed maturities amortized cost, After five years through ten years	8,797
Fixed maturities fair value, After five years through ten years	9,211
Fixed maturities fair value, After five years through ten years, Percent	30.00%
Fixed maturities amortized cost, After ten years	4,374
Fixed maturities fair value, After ten years	4,695
Fixed maturities fair value, After ten years, Percent	15.00%
Fixed maturities amortized cost, Subtotal	18,862
Fixed maturities fair value, Subtotal	19,954
Fixed maturities fair value, Subtotal, Percent	65.00%
Fixed maturities amortized cost, ABS	3,872
Fixed maturities fair value, ABS	3,887
Fixed maturities fair value, ABS, Percent	13.00%
Fixed maturities amortized cost, MBS	6,340
Fixed maturities fair value, MBS	6,893
Fixed maturities fair value, MBS, Percent	22.00%
Fixed maturity [Member]
The scheduled maturities of available for sale fixed maturities
Amortized Cost	29,074
Fair Value	$30,734
Fair value, Total, Percent	100.00%

Investments_Details_4

Investments (Details 4) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
In Millions, unless otherwise specified
Unrealized gain on:
Pretax	$1,162		$880
Deferred Tax and Amounts Attributable to Noncontrolling Interests	-419		-317
Net	743	[1]	563	[1]	823	[1]	578
Fixed maturities - annuity segment [Member]
Unrealized gain on:
Pretax	1,157	[2]	729	[2]
Deferred Tax and Amounts Attributable to Noncontrolling Interests	-405	[2]	-255	[2]
Net	752	[2]	474	[2]
Fixed maturities - all other [Member]
Unrealized gain on:
Pretax	503		361
Deferred Tax and Amounts Attributable to Noncontrolling Interests	-185		-133
Net	318		228
Equity securities [Member]
Unrealized gain on:
Pretax	218		192
Deferred Tax and Amounts Attributable to Noncontrolling Interests	-79		-70
Net	139		122
Deferred policy acquisition costs - annuity segment [Member]
Unrealized gain on:
Pretax	-531		-345
Deferred Tax and Amounts Attributable to Noncontrolling Interests	186		121
Net	-345		-224
Annuity benefits accumulated [Member]
Unrealized gain on:
Pretax	-112		-71
Deferred Tax and Amounts Attributable to Noncontrolling Interests	39		25
Net	-73		-46
Life, accident and health reserves [Member]
Unrealized gain on:
Pretax	-104		-8
Deferred Tax and Amounts Attributable to Noncontrolling Interests	36		3
Net	-68		-5
Unearned revenue [Member]
Unrealized gain on:
Pretax	31		22
Deferred Tax and Amounts Attributable to Noncontrolling Interests	-11		-8
Net	$20		$14
[1]	Includes net unrealized gains of $58 million at December 31, 2014 compared to net unrealized gains of $54 million and $33 million at December 31, 2013 and 2012, related to securities for which only the credit portion of an other-than-temporary impairment has been recorded in earnings.
[2]	Unrealized gains on fixed maturity investments supporting AFG’s annuity benefits accumulated.

Investments_Details_5

Investments (Details 5) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Net Investment Income [Line Items]
Gross investment income	$1,513	$1,363		$1,318
Investment expenses	-12	-17		-17
Net investment income	1,501	1,346		1,301
Fixed maturities [Member]
Net Investment Income [Line Items]
Gross investment income	1,352	1,241		1,216
Equity securities [Member]
Net Investment Income [Line Items]
Gross investment income	66	50		36
Equity Method Investments [Member]
Net Investment Income [Line Items]
Gross investment income	18	0	[1]	0	[1]
Other [Member]
Net Investment Income [Line Items]
Gross investment income	$77	$72		$66
[1]	Equity in the earnings of partnerships has not been material and was included in realized gains (losses) on securities prior to 2014.

Investments_Details_6

Investments (Details 6) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	$88	$233	$236
Realized - impairments	-36	-12	-26
Fixed maturities [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	36	36	55
Realized - impairments	-15	-5	-9
Change in unrealized	570	-945	790
Equity securities [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	53	196	192
Realized - impairments	-26	-5	-24
Change in unrealized	26	31	-23
Mortgage Loans and Other Investments [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	1	2	-3
Realized - impairments	0	-5	0
Change in unrealized	0	0	0
Other, Including DPAC and Reserves on Annuity and Long-term Care [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	-2	-1	-8
Realized - impairments	5	3	7
Change in unrealized	-314	504	-379
Tax Effects [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	-32	-82	-83
Realized - impairments	13	4	9
Change in unrealized	-99	144	-136
Noncontrolling Interests [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	-2	-2	-2
Realized - impairments	1	0	0
Change in unrealized	-3	6	-7
Marketable Securities [Member]
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	54	149	151
Realized - impairments	-22	-8	-17
Change in unrealized	$180	($260)	$245

Investments_Details_7

Investments (Details 7) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fixed maturities [Member]
Gross realized gains and losses on the sale of available for sale fixed maturity and equity security investments
Gross gains	$36	$44	$55
Gross losses	-2	-5	-4
Equity securities [Member]
Gross realized gains and losses on the sale of available for sale fixed maturity and equity security investments
Gross gains	53	193	196
Gross losses	$0	$0	($4)

Investments_Details_Textual

Investments (Details Textual) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Investment [Line Items]
Percentage (based on amount of unrealized loss) of available for sale fixed maturities that are in an unrealized loss position and rated investment grade	70.00%
Percentage (based on fair value) of available for sale fixed maturities that are in an unrealized loss position and rated investment grade	85.00%
Other than temporary impairment charges	$36	$12	$26
Average life of ABS	4 years 6 months
Average life of MBS	4 years 6 months
Percentage increase in shareholders' equity	10.00%	10.00%
Residential Mortgage Backed Securities [Member]
Investment [Line Items]
Non-credit related portion of other-than-temporary impairment charges taken for securities still owned	220	229
Fixed maturities, Gross Unrealized, Losses	-15	-28
Securities with non-credit other-than-temporary impairment charges [Member]
Investment [Line Items]
Gross Unrealized, Gains	151	150
Gross Unrealized, Losses	-8	-13
Fixed maturities [Member]
Investment [Line Items]
Fixed maturities, Gross Unrealized, Losses	-79	-305
Number of available for sale securities in an unrealized loss position	650
Other than temporary impairment charges	15	5	9
Common stocks [Member]
Investment [Line Items]
Number of available for sale securities in an unrealized loss position	34
Other than temporary impairment charges	26
Equity securities, Gross Unrealized, Losses	-25	-16
Preferred stocks [Member]
Investment [Line Items]
Number of available for sale securities in an unrealized loss position	19
Equity securities, Gross Unrealized, Losses	-5	-10
Maximum [Member] | Residential Mortgage Backed Securities [Member]
Investment [Line Items]
Other than temporary impairment charges	1
Maximum [Member] | Preferred stocks [Member]
Investment [Line Items]
Other than temporary impairment charges	$1
Number of available for sale securities in an unrealized loss position for twelve months or longer [Member] | Common stocks [Member]
Investment [Line Items]
Number of available for sale securities in an unrealized loss position	0
Number of available for sale securities in an unrealized loss position for twelve months or longer [Member] | Preferred stocks [Member]
Investment [Line Items]
Number of available for sale securities in an unrealized loss position	8

Derivatives_Details

Derivatives (Details) (Not Designated as Hedging Instrument [Member], USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Derivatives included in AFG' s Balance Sheet at fair value
Derivative asset, at fair value	$499	$433
Derivative liability, at fair value	1,173	814
MBS with embedded derivatives [Member] | Fixed maturities [Member]
Derivatives included in AFG' s Balance Sheet at fair value
Derivative asset, at fair value	158	140
Public company warrants [Member] | Equity securities [Member]
Derivatives included in AFG' s Balance Sheet at fair value
Derivative asset, at fair value	19	19
Interest rate swaptions [Member] | Other investments [Member]
Derivatives included in AFG' s Balance Sheet at fair value
Derivative asset, at fair value	0	2
Fixed-indexed annuities (embedded derivative) [Member] | Annuity benefits accumulated [Member]
Derivatives included in AFG' s Balance Sheet at fair value
Derivative liability, at fair value	1,160	804
Equity index call options [Member] | Other investments [Member]
Derivatives included in AFG' s Balance Sheet at fair value
Derivative asset, at fair value	322	272
Reinsurance contracts (embedded derivative) [Member] | Other liabilities [Member]
Derivatives included in AFG' s Balance Sheet at fair value
Derivative liability, at fair value	$13	$10

Derivatives_Details_1

Derivatives (Details 1) (Not Designated as Hedging Instrument [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	($3)		$36		$4
MBS with embedded derivatives [Member] | Realized gains on securities [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	3		-3		5
Public company warrants [Member] | Realized gains on securities [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	0		3		0
Interest rate swaptions [Member] | Realized gains on securities [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	-2		1		-4
Fixed-indexed annuities (embedded derivative) [Member] | Annuity benefits [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	-182	[1]	-182	[1]	-57	[1]
Equity index call options [Member] | Annuity benefits [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	181		210		66
Reinsurance contracts (embedded derivative) [Member] | Net investment income [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	($3)		$7		($6)
[1]	The change in fair value of the embedded derivative includes gains related to unlocking of actuarial assumptions of $58 million in 2014, $2 million in 2013 and $36 million in 2012.

Derivatives_Details_Textual

Derivatives (Details Textual) (USD $)	12 Months Ended			3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Indexed annuities as a percentage of annuity benefits	50.00%
Carrying value of collateral received to support purchased call options	$285
Not Designated as Hedging Instrument [Member] | Interest rate swaptions [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivative asset instrument outstanding	200
Payments to purchase swaptions	4
Not Designated as Hedging Instrument [Member] | Annuity benefits [Member] | Fixed-indexed annuities (embedded derivative) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
The portion of the change in fair value of the embedded derivative related to the unlocking of actuarial assumptions	58	2	36
Cash Flow Hedges [Member] | Designated as Hedging Instrument [Member] | Interest rate swaptions [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Contract term of derivative instrument				5 years
Notional amount of derivative instrument outstanding	401			431
Gain (loss) reclassified from AOCI into net investment income	2
Maximum [Member] | Cash Flow Hedges [Member] | Designated as Hedging Instrument [Member] | Interest rate swaptions [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives, at fair value (are less than)	($1)
LIBOR [Member] | Cash Flow Hedges [Member] | Designated as Hedging Instrument [Member] | Interest rate swaptions [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Description of variable interest rate of derivative instrument				one-month LIBOR

Deferred_Policy_Acquisition_Co2

Deferred Policy Acquisition Costs (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Movement Analysis of Deferred Policy Acquisition Costs and Present Value of Future Profits [Roll Forward]
Deferred policy acquisition costs and present value of future profits, beginning balance	$975	$550	$901
Deferred policy acquisition costs and present value of future profits, additions	703	701	665
Deferred policy acquisition costs and present value of future profits, periodic amortization	-652	-644	-618
Deferred policy acquisition costs and present value of future profits, annuity unlocking	-20	2	-37
Deferred policy acquisition costs and present value of future profits, loss recognition charge			-79
Deferred policy acquisition costs and present value of future profits, change included in realized gains	3	2	-1
Deferred policy acquisition costs and present value of future profits, foreign currency translation	-2	-1
Deferred policy acquisition costs and present value of future profits, sale of subsidiaries			-108
Deferred policy acquisition costs and present value of future profits, change in unrealized	-186	365	-173
Deferred policy acquisition costs and present value of future profits, ending balance	821	975	550
Property and Casualty Insurance [Member]
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs, beginning balance	211	204	189
Deferred policy acquisition costs, additions	497	468	438
Deferred policy acquisition costs, periodic amortization	-485	-460	-423
Deferred policy acquisition costs, foreign currency translation	-2	-1
Deferred policy acquisition costs, ending balance	221	211	204
Annuity and Other [Member]
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs, beginning balance	875	787	916
Deferred policy acquisition costs, additions	198	222	212
Deferred policy acquisition costs, periodic amortization	-130	-140	-148
Deferred policy acquisition costs, annuity unlocking	-20	4	-33
Deferred policy acquisition costs, loss recognition charge			-67
Deferred policy acquisition costs, change included in realized gains	2	2	-1
Deferred policy acquisition costs, sale of subsidiaries			-92
Deferred policy acquisition costs, ending balance	925	875	787
Movement in Deferred Sales Inducements [Roll Forward]
Deferred sales inducements, beginning balance	149	170	189
Deferred sales inducements, additions	8	11	15
Deferred sales inducements, periodic amortization	-26	-30	-30
Deferred sales inducements, annuity unlocking	0	-2	-4
Deferred sales inducements, change included in realized gains	1	0	0
Deferred sales inducements, ending balance	132	149	170
Movement in Present Value of Future Insurance Profits [Roll Forward]
Present value of future profits, beginning balance	85	99	144
Present value of future profits, periodic amortization	-11	-14	-17
Present value of future profits, annuity unlocking			0
Present value of future profits, loss recognition charge			-12
Present value of future profits, sale of subsidiaries			-16
Present value of future profits, ending balance	74	85	99
Movement in Unrealized Gains (Losses) Related to Deferred Policy Acquisition Costs and Present Value of Future Profits [Roll Forward]
Unrealized investment gains (losses), beginning balance	-345	-710	-537
Unrealized investment gains (losses), change in unrealized	-186	365	-173
Unrealized investment gains (losses), ending balance	-531	-345	-710
Movement Analysis of Deferred Policy Acquisition Costs and Present Value of Future Profits [Roll Forward]
Deferred policy acquisition costs and present value of future profits, beginning balance	764	346	712
Deferred policy acquisition costs and present value of future profits, additions	206	233	227
Deferred policy acquisition costs and present value of future profits, periodic amortization	-167	-184	-195
Deferred policy acquisition costs and present value of future profits, annuity unlocking	-20	2	-37
Deferred policy acquisition costs and present value of future profits, loss recognition charge			-79
Deferred policy acquisition costs and present value of future profits, change included in realized gains	3	2	-1
Deferred policy acquisition costs and present value of future profits, sale of subsidiaries			-108
Deferred policy acquisition costs and present value of future profits, change in unrealized	-186	365	-173
Deferred policy acquisition costs and present value of future profits, ending balance	$600	$764	$346

Deferred_Policy_Acquisition_Co3

Deferred Policy Acquisition Costs (Details Textual) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred Policy Acquisition Costs Disclosures [Abstract]
Accumulated amortization of present value of future profits	$209	$198
Approximate annual rate of decrease in present value of future profits during next five years	0.167

Managed_Investment_Entities_De

Managed Investment Entities (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Gains (losses) on change in fair value of assets/liabilities:
Assets	($66)	[1]	$11	[1]	$95	[1]
Liabilities	22	[1]	-25	[1]	-189	[1]
Management fees paid to AFG	25		16		18
CLO earnings (losses) attributable to:
AFG shareholders	16	[2]	35	[2]	31	[2]
Noncontrolling interests	($51)	[2]	($26)	[2]	($98)	[2]
[1]	Included in Revenues in AFG’s Statement of Earnings.
[2]	Included in Earnings before income taxes in AFG’s Statement of Earnings.

Managed_Investment_Entities_De1

Managed Investment Entities (Details Textual) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	collateralizedloanobligation	collateralizedloanobligation	collateralizedloanobligation
Variable Interest Entity [Line Items]
Percentage of investment of most subordinate debt tranche, Minimum	15.00%
Percentage of investment of most subordinate debt tranche, Maximum	51.20%
Number of collateralized loan obligation entities	12
Number of collateralized loan obligation entities formed during the period	2	2	2
Proceeds received by subsidiaries related to redemptions of managed investment entities liabilities	$81	$142	$12
Number of collateralized loan obligation entities that were substantially liquidated during the period	4	2
Difference between aggregate unpaid principal balance and fair value of CLOs' fixed maturity investments	83	15
Difference between aggregate unpaid principal balance and fair value of CLOs' debt	131	109
Carrying amount of CLO loans in default	2	1
Aggregate unpaid principal balance of CLO loans in default	6	6
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Aggregate fair value of investment in collateralized loan obligations	289	271
New Collateralized Loan Obligation Entities [Member]
Variable Interest Entity [Line Items]
Face value of liabilities issued by managed investment entities on issuance date	917	829	860
Face amount of managed investment entities liabilities purchased by subsidiaries at issuance date	94	85	74
Subordinated Debt Obligations [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Aggregate fair value of investment in collateralized loan obligations	92
Senior Debt Obligations [Member]
Variable Interest Entity [Line Items]
Face amount of managed investment entities liabilities purchased by subsidiaries after issuance date	13	94	74
Amount paid by subsidiaries to purchase managed investment entities liabilities after issuance date	$13	$89	$69

Goodwill_and_Other_Intangibles2

Goodwill and Other Intangibles (Details) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Sep. 30, 2012	Dec. 31, 2014	Dec. 31, 2012
Changes in the carrying value of goodwill by reporting segment
Goodwill, Beginning balance			$185	$186
Goodwill, Sale of subsidiary		-1		-1
Goodwill, Acquired during period	16		16
Goodwill, Ending balance			201	185
Property and Casualty [Member]
Changes in the carrying value of goodwill by reporting segment
Goodwill, Beginning balance			152	152
Goodwill, Sale of subsidiary				0
Goodwill, Acquired during period			16
Goodwill, Ending balance			168	152
Annuity [Member]
Changes in the carrying value of goodwill by reporting segment
Goodwill, Beginning balance			33	34
Goodwill, Sale of subsidiary				-1
Goodwill, Acquired during period			0
Goodwill, Ending balance			$33	$33

Goodwill_and_Other_Intangibles3

Goodwill and Other Intangibles (Details Textual) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Sep. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill acquired during period	$16		$16
Goodwill decrease due to the sale of a small annuity subsidiary		-1			-1
Amortizable intangible assets related to property and casualty insurance acquisitions			49	14
Accumulated amortization			91	75
Amortization of intangible assets			19	14	14
Weighted average useful life of finite-lived intangible assets acquired			6 years
Future amortization of intangibles in next year			8
Future amortization of intangibles in year two			8
Future amortization of intangibles in year three			8
Future amortization of intangibles in year four			8
Future amortization of intangibles in year five			8
Future amortization of intangibles after year five			$9

LongTerm_Debt_Details

Long-Term Debt (Details) (USD $)	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Summary of Carrying value of long-term debt
Long-term debt	$1,061		$913
AFG [Member]
Summary of Carrying value of long-term debt
Long-term debt	990		840
Subsidiaries [Member]
Summary of Carrying value of long-term debt
Long-term debt	71		73
Notes payable secured by real estate due 2015 through 2016	59		61
National Interstate bank credit facility	12		12
9-7/8% Senior Notes due June 2019 [Member] | AFG [Member]
Summary of Carrying value of long-term debt
Senior Notes	350		350
6-3/8% Senior Notes due June 2042 [Member] | AFG [Member]
Summary of Carrying value of long-term debt
Senior Notes	230		230
5-3/4% Senior Notes due August 2042 [Member] | AFG [Member]
Summary of Carrying value of long-term debt
Senior Notes	125		125
7% Senior Notes due September 2050 [Member] | AFG [Member]
Summary of Carrying value of long-term debt
Senior Notes	132		132
Senior Debt Obligations [Member] | AFG [Member]
Summary of Carrying value of long-term debt
Other long-term debt	3		3
Long-term debt	840		840
6-1/4% Subordinated Debentures due September 2054 [Member] | AFG [Member]
Summary of Carrying value of long-term debt
Subordinated Debentures	$150	$150	$0

LongTerm_Debt_Details_1

Long-Term Debt (Details 1) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Summary showing division of total long-term debt
Obligations secured by real estate	$59	$61
Long-term debt	1,061	913
Senior unsecured obligations [Member]
Summary showing division of total long-term debt
Unsecured obligations	852	852
Subordinated unsecured obligations [Member]
Summary showing division of total long-term debt
Unsecured obligations	$150	$0

LongTerm_Debt_Details_Textual

Long-Term Debt (Details Textual) (USD $)	12 Months Ended			0 Months Ended	1 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Jun. 30, 2012	Aug. 31, 2012	Sep. 30, 2014
Debt Instrument [Line Items]
Scheduled principal payments on debt in next year	$14			$14
Scheduled principal payments on debt in year two	45			45
Scheduled principal payments on debt in year three	12			12
Scheduled principal payments on debt in year four	0			0
Scheduled principal payments on debt in year five	350			350
Scheduled principal payments on debt after year five	640			640
Cash interest payments on long-term debt	72	71	75
AFG [Member]
Debt Instrument [Line Items]
Revolving credit line	500			500
Interest rate on revolving debt facility				1.38%
Amount borrowed under AFG revolving credit facility	0	0		0
Interest rate description for revolving credit facility	1.00% to 1.875% (currently 1.375%) over LIBOR
AFG [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate on revolving debt facility				1.00%
AFG [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate on revolving debt facility				1.88%
National Interstate [Member]
Debt Instrument [Line Items]
Revolving credit line	100			100
Interest rate on revolving debt facility				1.20%
Loans payable under National Interstate bank credit facility	12			12
Interest rate description for revolving credit facility	six-month LIBOR plus 0.875% (currently 1.20%)
National Interstate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate on revolving debt facility				0.88%
9-7/8% Senior Notes due June 2019 [Member]
Debt Instrument [Line Items]
Interest rate on debt instruments	9.88%			9.88%
9-7/8% Senior Notes due June 2019 [Member] | AFG [Member]
Debt Instrument [Line Items]
Senior Notes	350	350		350
6-3/8% Senior Notes due June 2042 [Member]
Debt Instrument [Line Items]
Interest rate on debt instruments	6.38%			6.38%
6-3/8% Senior Notes due June 2042 [Member] | AFG [Member]
Debt Instrument [Line Items]
Senior Notes	230	230		230
Proceeds from Issuance of Senior Long-term Debt					230
5-3/4% Senior Notes due August 2042 [Member]
Debt Instrument [Line Items]
Interest rate on debt instruments	5.75%			5.75%
5-3/4% Senior Notes due August 2042 [Member] | AFG [Member]
Debt Instrument [Line Items]
Senior Notes	125	125		125
Proceeds from Issuance of Senior Long-term Debt						125
7% Senior Notes due September 2050 [Member]
Debt Instrument [Line Items]
Interest rate on debt instruments	7.00%			7.00%
7% Senior Notes due September 2050 [Member] | AFG [Member]
Debt Instrument [Line Items]
Senior Notes	132	132		132
6-1/4% Subordinated Debentures due September 2054 [Member]
Debt Instrument [Line Items]
Interest rate on debt instruments	6.25%			6.25%
6-1/4% Subordinated Debentures due September 2054 [Member] | AFG [Member]
Debt Instrument [Line Items]
Subordinated Debentures	$150	$0		$150			$150
7-1/2% Senior Debentures due November 2033 [Member]
Debt Instrument [Line Items]
Interest rate on debt instruments					7.50%
7-1/4% Senior Debentures due January 2034 [Member]
Debt Instrument [Line Items]
Interest rate on debt instruments					7.25%
7-1/8% Senior Debentures due February 2034 [Member]
Debt Instrument [Line Items]
Interest rate on debt instruments						7.13%

Shareholders_Equity_Details

Shareholders' Equity (Details) (USD $)	Dec. 31, 2014
In Millions, except Per Share data, unless otherwise specified
Voting Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, par value	$0
Preferred Stock, shares authorized	12.5
Nonvoting Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, par value	$0
Preferred Stock, shares authorized	12.5

Shareholders_Equity_Details_1

Shareholders' Equity (Details 1) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, Beginning balance	6,608,614
Granted	1,047,375
Exercised	-1,262,313
Forfeited/Cancelled	-9,877
Options outstanding, Ending balance	6,383,799	6,608,614
Options exercisable	3,465,644
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Average exercise price, Beginning balance	$32.16
Average exercise price, Granted	$56.47	$44.01	$38.10
Average exercise price, Exercised	$28.19
Average exercise price, Forfeited/Cancelled	$42.22
Average exercise price, Ending balance	$36.92	$32.16
Average exercise price, Options exercisable	$30.04
Average remaining contractual term, Options outstanding	5 years 9 months 18 days
Average remaining contractual term, Options exercisable	4 years 1 month 6 days
Aggregate intrinsic value, Options outstanding	$152
Aggregate intrinsic value, Options exercisable	$106

Shareholders_Equity_Details_2

Shareholders' Equity (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Options, Valuation Assumptions
Exercise price	$56.47	$44.01	$38.10
Expected dividend yield	1.60%	1.80%	1.80%
Expected volatility	26.00%	39.00%	39.00%
Expected term (in years)	7 years 3 months	7 years 3 months	7 years 3 months
Risk-free rate	2.20%	1.36%	1.40%
Grant date fair value	$14.66	$15.10	$13.02

Shareholders_Equity_Details_3

Shareholders' Equity (Details 3) (Restricted Stock [Member], USD $)	12 Months Ended
	Dec. 31, 2014
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, Beginning balance	552,569
Granted	102,330
Vested	-139,449
Outstanding, Ending balance	515,450
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Average grant date fair value, Outstanding, Beginning balance	$37.79
Average grant date fair value, Granted	$56.44
Average grant date fair value, Vested	$31.05
Average grant date fair value, Outstanding, Ending balance	$43.32

Shareholders_Equity_Details_4

Shareholders' Equity (Details 4) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Components of accumulated other comprehensive income
Unrealized holding gains (losses) on securities arising during the period, pretax	$334		($188)
Unrealized holding gains (losses) on securities arising during the period, tax	-118		66
Unrealized holding gains (losses) on securities arising during the period, net of tax	216		-122		408
Unrealized holding gains (losses) on securities arising during the period, attributable to noncontrolling interests	-4		4
Unrealized holding gains (losses) on securities arising during the period, attributable to shareholders	212		-118
Reclassification adjustment for realized gains (losses) included in net earnings, pretax	-52	[1]	-222	[1]
Reclassification adjustment for realized gains (losses) included in net earnings, tax	19	[1]	78	[1]
Reclassification adjustment for realized gains (losses) included in net earnings, net of tax	-33		-144		-138
Reclassification adjustment for realized gains (losses) included in net earnings, attributable to noncontrolling interests	1	[1]	2	[1]
Reclassification adjustment for realized gains (losses) included in net earnings, attributable to shareholders	-32		-142
Accumulated other comprehensive income, net unrealized gains on securities, beginning balance	563	[2]	823	[2]	578
Other comprehensive income, net unrealized gains on securities, pretax	282		-410		388
Other comprehensive income, net unrealized gains on securities, tax	-99		144		-136
Total net unrealized gains (losses) on securities	183		-266		252
Other comprehensive income, net unrealized gains on securities, attributable to noncontrolling interests	-3		6		-7
Other comprehensive income, net unrealized gains on securities, attributable to shareholders	180		-260		245
Other change in accumulated other comprehensive income, available for sale securities adjustments	0		0		0	[3]
Accumulated other comprehensive income, net unrealized gains on securities, ending balance	743	[2]	563	[2]	823	[2]
Accumulated other comprehensive income, foreign currency translation adjustments, beginning balance	1		14		10
Other comprehensive income, foreign currency translation adjustments, pretax	-9		-13		6
Other comprehensive income, foreign currency translation adjustments, net of tax	-9		-13		6
Other comprehensive income, foreign currency translation adjustments, attributable to noncontrolling interests	0		0		-1
Other comprehensive income, foreign currency translation adjustments, attributable to shareholders	-9		-13		5
Other change in accumulated other comprehensive income, foreign currency translation adjustments	0		0		-1	[3]
Accumulated other comprehensive income, foreign currency translation adjustments, ending balance	-8		1		14
Accumulated other comprehensive income, pension and other postretirement plans adjustments, beginning balance	-4		-6		-8
Other comprehensive income, pension and other postretirement plans adjustments, pretax	-6		3		2
Other comprehensive income, pension and other postretirement plans adjustments, tax	2		-1		0
Other comprehensive income, pension and other postretirement plans adjustments, net of tax	-4		2		2
Other comprehensive income, pension and other postretirement plans adjustments, attributable to shareholders	-4		2		2
Accumulated other comprehensive income, pension and other postretirement plans adjustments, ending balance	-8		-4		-6
Accumulated other comprehensive income, total, beginning balance	560		831		580
Other comprehensive income, total, pretax	267		-420		396
Other comprehensive income, total, tax	-97		143		-136
Other comprehensive income (loss), net of tax	170		-277		260
Other comprehensive income, total, attributable to noncontrolling interests	-3		6		-8
Other comprehensive income, total, attributable to shareholders	167		-271		252
Other change in accumulated other comprehensive income, total	0		0		-1	[3]
Accumulated other comprehensive income, total, ending balance	$727		$560		$831
[1]	The reclassification adjustment out of net unrealized gains on securities affected the following lines in AFG’s Consolidated Statement of Earnings: OCI component Affected line in the Consolidated Statement of Earnings Pretax Realized gains on securities Tax Provision for income taxes Attributable to noncontrolling interests Net earnings (loss) attributable to noncontrolling interests
[2]	Includes net unrealized gains of $58 million at December 31, 2014 compared to net unrealized gains of $54 million and $33 million at December 31, 2013 and 2012, related to securities for which only the credit portion of an other-than-temporary impairment has been recorded in earnings.
[3]	Other relates to the 2012 acquisition of noncontrolling interest in a subsidiary.

Shareholders_Equity_Details_Te

Shareholders' Equity (Details Textual) (USD $)	12 Months Ended			3 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Rate of options exercisable per year, commencing one year after grant	20% per year commencing one year after grant
Duration of options expiration, after date of grant	10 years
Total intrinsic value of options exercised	$38	$35	$25
Cash received from the exercise of stock options	35	44	40
Tax benefit related to exercise of stock options	12	11	8
Total compensation expense related to stock incentive plans	25	36	26
Tax benefit related to compensation costs	8	12	8
Net of tax unrealized gains (losses) related to credit-only impaired securities	58	54	33
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Common Stock vesting period	3 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Common Stock vesting period	4 years
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to equity-based awards that have yet to vest	30
Weighted average period of cost expected to be recognized	3 years 2 months 12 days
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to equity-based awards that have yet to vest	$11
Weighted average period of cost expected to be recognized	2 years 3 months 18 days
Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock reserved for issuance under stock incentive plans	10,200,000
Annual Equity Bonus Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other benefit plans, shares				84,036	88,602
Common Stock issued, fair value per share				$57.16	$47.12

Income_Taxes_Details

Income Taxes (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of income taxes at the statutory rate and income taxes shown in the Statement of Earnings
Earnings before income taxes (“EBT”)	$626	$689	$537
Income taxes at statutory rate	219	241	188
Income taxes at statutory rate as a percentage of EBT	35.00%	35.00%	35.00%
Effect of tax exempt interest	-25	-21	-23
Effect of tax exempt interest as a percentage of EBT	-4.00%	-3.00%	-4.00%
Effect of losses of managed investment entities	18	9	34
Effect of losses of managed investment entities as a percentage of EBT	3.00%	1.00%	6.00%
Effect of change in valuation allowance	7	1	3
Effect of change in valuation allowance as a percentage of EBT	1.00%	0.00%	1.00%
Effect of subsidiaries not in AFG's tax return	1	2	-1
Effect of subsidiaries not in AFG's tax return as a percentage of EBT	0.00%	0.00%	0.00%
Effect of tax case and settlement of open tax years	0	0	-67
Effect of tax case and settlement of open tax years as a percentage of EBT	0.00%	0.00%	-13.00%
Effect of other income tax reconciliation	0	4	1
Effect of other income tax reconciliation as a percentage of EBT	0.00%	1.00%	0.00%
Provision for income taxes as shown in the Statement of Earnings	$220	$236	$135
Provision for income taxes as shown in the Statement of Earnings as a percentage of EBT	35.00%	34.00%	25.00%

Income_Taxes_Details_1

Income Taxes (Details 1) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current taxes:
Federal	$265	$308	$146
State	8	5	6
Deferred taxes:
Federal	-53	-77	-17
Provision for income taxes as shown in the Statement of Earnings	$220	$236	$135

Income_Taxes_Details_2

Income Taxes (Details 2)	Dec. 31, 2014	Dec. 31, 2014		Dec. 31, 2014
In Millions, unless otherwise specified	U.S. [Member]	United Kingdom [Member]		United Kingdom [Member]
	Expiring 2017 - 2024 [Member]	USD ($)		GBP (£)
	USD ($)
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$144	$131	[1]	£ 85	[1]
[1]	£85 million

Income_Taxes_Details_3

Income Taxes (Details 3) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Deferred tax assets:
Federal net operating loss carryforwards	$51		$51
Foreign underwriting losses	56		50
Insurance claims and reserves	746		558
Employee benefits	107		98
Other, net	26		51
Total deferred tax assets before valuation allowance	986		808
Valuation allowance against deferred tax assets	-109		-103
Total deferred tax assets	877		705
Deferred tax liabilities:
Subsidiaries not in AFG’s tax return	-61	[1]	-60	[1]
Investment securities	-663		-443
Deferred policy acquisition costs	-178		-234
Total deferred tax liabilities	-902		-737
Net deferred tax liability	($25)		($32)
[1]	Related to National Interstate Corporation, a 51%-owned subsidiary.

Income_Taxes_Details_4

Income Taxes (Details 4) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Progression of the liability for uncertain tax positions, excluding interest and penalties
Balance at January 1			$19	$18	$59
Reductions for tax positions of prior years		-10	-8	0	-46
Additions for tax positions of current year			0	1	5
Settlements	-11		-11	0	0
Balance at December 31			$0	$19	$18

Income_Taxes_Details_Textual

Income Taxes (Details Textual)

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2012

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Sep. 30, 2012

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2014

Sep. 30, 2014

Sep. 30, 2014

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Tax litigation settlement [Member]

Tax litigation settlement [Member]

AFG [Member]

AFG [Member]

AFG [Member]

Charge for valuation allowance [Member]

Maximum [Member]

United Kingdom [Member]

United Kingdom [Member]

Timing of recognition of investment income [Member]

Deductibility of certain financing expenses [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

GBP (£)

USD ($)

USD ($)

Income Tax Reconciliation [Line Items]

Statutory rate of income taxes

35.00%

35.00%

35.00%

Tax benefit related to settlement of litigation

$39

$28

Expected refund of tax and interest paid related to tax settlements

17

Income (losses) subject to tax in foreign jurisdictions (are less than in 2014)

12

-3

-1

Operating loss carryforwards

131

[1]

85

[1]

Percentage ownership of National Interstate

51.00%

Charge for valuation allowance against deferred tax assets

56

Operating loss carryforwards, valuation allowance

50

Decrease in AFG's liability for uncertain tax positions

-19

-17

-2

Decrease in AFG's liability for uncertain tax positions, settlements

-11

-11

0

0

The portion of the reduction in the liability for uncertain tax positions that favorably impacted the effective tax rate

4

Change in AFG's liability for uncertain tax positions of current year, uncertainty as to timing of tax return inclusion of income related to certain securities

1

3

Change in AFG's liability for uncertain tax positions of current year related to deductibility of certain expenses

2

Change in AFG's liability for uncertain tax positions of prior year related to resolution of tax case

36

Change in AFG's related liability for interest for uncertain tax positions

14

Change in AFG's liability for uncertain tax positions of prior year

-10

-8

0

-46

Interest included in tax provision

-1

1

-14

Decrease in related accrued interest

1

Income tax penalties accrued

0

Cash payments for income taxes

$347

$204

$277

[1]

£85 million

Contingencies_Details

Contingencies (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2014
Property and Casualty Group [Member]
Loss Contingencies [Line Items]
Increase in asbestos and environmental reserves	$24	$54	$31
Liability for asbestos and environmental reserves				366
Reinsurance recoverables on asbestos and environmental reserves, net of allowance				77
Former railroad and manufacturing operations [Member]
Loss Contingencies [Line Items]
Increase in environmental and other reserves	6	22	2
American Premier and its subsidiaries [Member]
Loss Contingencies [Line Items]
Liability for environmental and other claims				80
GAFRI [Member]
Loss Contingencies [Line Items]
Liability for environmental and other claims				$10

Quarterly_Operating_Results_Un2

Quarterly Operating Results (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Statement of Earnings
Revenues	$1,529	$1,581	$1,392	$1,211	$1,362	$1,443	$1,139	$1,148	$5,713	$5,092	$4,957
Net earnings, including noncontrolling interests	125	91	83	107	165	98	77	113	406	453	402
Net earnings attributable to shareholders	$127	$116	$106	$103	$158	$83	$110	$120	$452	$471	$488
Earnings Attributable to Shareholders per Common Share:
Basic (USD per share)	$1.44	$1.30	$1.18	$1.15	$1.77	$0.94	$1.23	$1.34	$5.07	$5.27	$5.18
Diluted (USD per share)	$1.41	$1.28	$1.15	$1.13	$1.73	$0.92	$1.20	$1.32	$4.97	$5.16	$5.09
Average number of Common Shares:
Basic (shares)	87.9	89	89.6	89.6	89.4	89.1	89.6	89.4	89	89.3	94.2
Diluted (shares)	89.8	90.9	91.6	91.6	91.4	91	91.5	91	91	91.2	95.9

Quarterly_Operating_Results_Un3

Quarterly Operating Results (Unaudited) (Details 1) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Realized gains (losses) and favorable (adverse) development on unpaid loss and loss adjustment expenses
Realized Gains	$8	$13	$12	$19	$63	$56	$41	$57	$52	$217
Prior Year Development Favorable (Adverse)	($10)	($13)	($14)	$31	$5	($40)	$22	$28	($6)	$15	$30

Quarterly_Operating_Results_Un4

Quarterly Operating Results (Unaudited) (Details Textual) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Operating Results (Unaudited) [Line Items]
Adverse prior year development in the property and transportation sub-segment	($10)	($13)	($14)	$31	$5	($40)	$22	$28	($6)	$15	$30
Property and Casualty Insurance [Member]
Quarterly Operating Results (Unaudited) [Line Items]
Special charges to increase asbestos and environmental reserves		24				54
Former Railroad and Manufacturing Operations [Member]
Quarterly Operating Results (Unaudited) [Line Items]
Special charges to increase asbestos and environmental reserves		6				22
Specialty Property and transportation [Member]
Quarterly Operating Results (Unaudited) [Line Items]
Adverse prior year development in the property and transportation sub-segment			($22)

Insurance_Details

Insurance (Details) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
Analysis of changes in the liability for losses and loss adjustment expenses, net of reinsurance
Balance at beginning of period				$4,288				$4,129	$4,288		$4,129	$4,282
Provision for losses and LAE occurring in the current year									2,488		2,055	1,903
Net increase (decrease) in provision for claims of prior years	10	13	14	-31	-5	40	-22	-28	6		-15	-30
Total losses and LAE incurred									2,494		2,040	1,873
Payments for losses and LAE of:
Current year									-789		-739	-841
Prior years									-1,340		-1,131	-1,185
Total payments									-2,129		-1,870	-2,026
Reserves of businesses acquired									1,028	[1]	0	0
Foreign currency translation and other									-36		-11	0
Balance at end of period	5,645				4,288				5,645		4,288	4,129
Add back reinsurance recoverables, net of allowance	2,227				2,122				2,227		2,122	2,716
Gross unpaid losses and LAE included in the Balance Sheet	$7,872				$6,410				$7,872		$6,410	$6,845
[1]	Reflects the acquisition of Summit in April 2014 (see Note B — “Acquisitions and Sales of Businesses”).

Insurance_Details_1

Insurance (Details 1) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property and casualty companies [Member]
Statutory information
Net Earnings	$318	$332	$221
Capital and Surplus	2,286	1,896
Life insurance companies [Member]
Statutory information
Net Earnings	349	294	171
Capital and Surplus	$1,714	$1,619

Insurance_Details_2

Insurance (Details 2) (Property and casualty insurance [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property and casualty insurance [Member]
Effects of Reinsurance [Line Items]
Direct premiums written	$5,387	$4,744	$4,283
Reinsurance assumed	90	61	38
Reinsurance ceded	-1,457	-1,464	-1,372
Net written premiums	4,020	3,341	2,949
Direct premiums earned	5,195	4,684	4,120
Reinsurance assumed	75	45	36
Reinsurance ceded	-1,392	-1,525	-1,309
Net earned premiums	3,878	3,204	2,847
Reinsurance recoveries	$895	$1,255	$1,743

Insurance_Details_3

Insurance (Details 3) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Insurance [Abstract]
Excess death and annuitization	$213	$197
Guaranteed withdrawal benefits	151	71
Accrued persistency and premium bonuses	$14	$15

Insurance_Details_Textual

Insurance (Details Textual) (USD $)	3 Months Ended	12 Months Ended			3 Months Ended			0 Months Ended	3 Months Ended
	Jun. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Mar. 31, 2014	Dec. 31, 2012
Insurance [Line Items]
Carrying value of securities owned by U.S.-based insurance subsidiaries on deposit		$1,180,000,000
Undrawn letters of credit		223,000,000
Undrawn letters of credit, collateralized		0
Workers' compensation insurance discount rate		4.50%	4.50%
Workers' compensation insurance discount, which has reduced the liability for unpaid losses and loss adjustment expenses		19,000,000	20,000,000
Long-term care insurance reserves, net of reinsurance recoverables		807,000,000
Investment in Federal Home Loan Bank capital stock		34,000,000
Proceeds received under funding agreements with the Federal Home Loan Bank	200,000,000
Advances from Federal Home Loan Bank		440,000,000	440,000,000
Description of variable rate basis		LIBOR
Estimated fair value of commercial mortgage-backed securities held as collateral by the Federal Home Loan Bank		544,000,000
Interest on advances from Federal Home Loan Bank (are less than in 2012)		1,000,000	1,000,000
Maximum amount of dividends available to be paid by insurance subsidiaries to AFG without prior approval of regulatory authorities		673,000,000
Dividends on Common Stock		-169,000,000	-161,000,000	-91,000,000
Catastrophe bond		59,000,000	61,000,000
Aggregate guaranteed minimum death benefit value on variable annuity polices in force		23,000,000	26,000,000
Minimum [Member]
Insurance [Line Items]
Dividends payments without violating the most restrictive debt covenants, minimum		1,000,000,000
Minimum [Member] | LIBOR [Member]
Insurance [Line Items]
FHLB advances, basis spread on variable rate		0.02%
Maximum [Member]
Insurance [Line Items]
Interest on advances from Federal Home Loan Bank (are less than in 2012)				1,000,000
Death benefits paid in excess of the variable annuity account balances (are less than in 2012, 2013 and 2014)		1,000,000	1,000,000	1,000,000
Maximum [Member] | LIBOR [Member]
Insurance [Line Items]
FHLB advances, basis spread on variable rate		0.23%
Average [Member] | LIBOR [Member]
Insurance [Line Items]
FHLB advances, basis spread on variable rate		0.32%
Property and Casualty Insurance [Member]
Insurance [Line Items]
Special charges to increase asbestos and environmental reserves					24,000,000	54,000,000	31,000,000
Catastrophe Bonds [Member]
Insurance [Line Items]
Catastrophe reinsurance coverage, excess retention amount								95,000,000
Catastrophe reinsurance coverage, retention amount								100,000,000
Catastrophe reinsurance coverage, annual cost		5,000,000
Life insurance [Member]
Insurance [Line Items]
Life insurance in force, ceded premiums		12,700,000,000	13,430,000,000
Life insurance in force, direct premiums		16,710,000,000	17,980,000,000
Life written premiums ceded		41,000,000	44,000,000	42,000,000
Run-off Long-term Care and Life [Member]
Insurance [Line Items]
Pretax charge on closed block of long-term care insurance		0	0						153,000,000
Unaffiliated Entity [Member] | Catastrophe Bonds [Member]
Insurance [Line Items]
Catastrophe bond								$95,000,000

Additional_Information_Details

Additional Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Additional Information (Textual) [Abstract]
Total rental expense	$65	$57	$51
Operating lease future minimum payments due in next year	62
Operating lease future minimum payments due in year two	59
Operating lease future minimum payments due in year three	50
Operating lease future minimum payments due in year four	42
Operating lease future minimum payments due in year five	38
Operating lease future minimum payments due after year five	174
Commitments to fund limited partnerships	370
Retirement and employee savings plan expense	30	32	27
Allowance for reinsurance recoverables [Member]
Allowance for reinsurance recoverables [Line Items]
Aggregate allowance for losses on reinsurance recoverables	25	27
Charges for possible losses on reinsurance recoverables (are less than in 2012)	4	1	1
Reinsurance recoverable write-offs	$6

Condensed_Financial_Informatio1

Condensed Financial Information of Parent Company (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
In Millions, unless otherwise specified
Assets:
Cash and cash equivalents	$1,343		$1,639		$1,705	$1,324
Total assets	47,535		42,087		39,171
Liabilities and Equity:
Long-term debt	1,061		913
Shareholders’ equity	4,879		4,599
Total liabilities and equity	47,535		42,087
AFG [Member]
Assets:
Cash and cash equivalents	292		523		279	415
Investment in securities	58		53
Investment in subsidiaries	5,638	[1]	5,041	[1]
Other investments	2		2
Other assets	103		108
Total assets	6,093		5,727
Liabilities and Equity:
Long-term debt	990		840
Other liabilities	224		288
Shareholders’ equity	4,879		4,599
Total liabilities and equity	$6,093		$5,727
[1]	Investment in subsidiaries includes intercompany receivables and payables.

Condensed_Financial_Informatio2

Condensed Financial Information of Parent Company (Details 1) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Total revenues	$1,529	$1,581	$1,392	$1,211	$1,362	$1,443	$1,139	$1,148	$5,713	$5,092	$4,957
Costs and Expenses:
Other expenses									281	326	326
Total costs and expenses									5,087	4,403	4,420
Earnings before income taxes									626	689	537
Provision for income taxes									220	236	135
Net Earnings Attributable to Shareholders	127	116	106	103	158	83	110	120	452	471	488
AFG [Member]
Revenues:
Dividends from subsidiaries									480	606	433
Equity in undistributed earnings of subsidiaries									332	260	325
Investment and other income									5	8	5
Total revenues									817	874	763
Costs and Expenses:
Interest charges on intercompany borrowings									10	10	11
Interest charges on other borrowings									69	67	61
Other expenses									66	90	68
Total costs and expenses									145	167	140
Earnings before income taxes									672	707	623
Provision for income taxes									220	236	135
Net Earnings Attributable to Shareholders									$452	$471	$488

Condensed_Financial_Informatio3

Condensed Financial Information of Parent Company (Details 2) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Other Comprehensive Income [Abstract]
Net earnings attributable to shareholders	$127	$116	$106	$103	$158	$83	$110	$120	$452	$471	$488
Other comprehensive income (loss), net of tax									167	-271	252
Comprehensive income attributable to shareholders									619	200	740
AFG [Member]
Statement of Other Comprehensive Income [Abstract]
Net earnings attributable to shareholders									452	471	488
Other comprehensive income (loss), net of tax									167	-271	252
Comprehensive income attributable to shareholders									$619	$200	$740

Condensed_Financial_Informatio4

Condensed Financial Information of Parent Company (Details 3) (USD $)	3 Months Ended								12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Activities:
Net earnings attributable to shareholders	$127	$116	$106	$103	$158	$83	$110	$120	$452	$471	$488
Adjustments:
Net cash provided by operating activities									1,222	760	817
Investing Activities:
Net cash used in investing activities									-3,619	-2,915	-1,425
Financing Activities:
Additional long-term borrowings									145	0	372
Reductions of long-term debt									-2	-40	-365
Issuances of Common Stock									47	54	46
Repurchases of Common Stock									-191	-70	-415
Cash dividends paid on Common Stock									-167	-160	-90
Net cash provided by (used in) financing activities									2,101	2,089	989
Net Change in Cash and Cash Equivalents									-296	-66	381
Cash and cash equivalents at beginning of year				1,639				1,705	1,639	1,705	1,324
Cash and cash equivalents at end of year	1,343				1,639				1,343	1,639	1,705
AFG [Member]
Operating Activities:
Net earnings attributable to shareholders									452	471	488
Adjustments:
Equity in net earnings of subsidiaries									-545	-579	-515
Dividends from subsidiaries									451	543	417
Other operating activities, net									14	-7	-10
Net cash provided by operating activities									372	428	380
Investing Activities:
Capital contributions to subsidiaries									-431	-38	-274
Returns of capital from subsidiaries									0	36	1
Purchases of investments, property and equipment									-1	-2	-11
Net cash used in investing activities									-432	-4	-284
Financing Activities:
Additional long-term borrowings									145	0	344
Reductions of long-term debt									0	0	-115
Issuances of Common Stock									42	50	44
Repurchases of Common Stock									-191	-70	-415
Cash dividends paid on Common Stock									-167	-160	-90
Net cash provided by (used in) financing activities									-171	-180	-232
Net Change in Cash and Cash Equivalents									-231	244	-136
Cash and cash equivalents at beginning of year				523				279	523	279	415
Cash and cash equivalents at end of year	$292				$523				$292	$523	$279

Supplementary_Insurance_Inform1

Supplementary Insurance Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs	$821	$975	$550
Reserves for future policy benefits, claims and unpaid losses and LAE	33,811	29,362	26,513
Unearned premiums	1,956	1,757	1,651
Net earned premiums	3,986	3,318	3,165
Net investment income	1,501	1,346	1,301
Benefits, claims, losses and settlement expenses	3,306	2,731	2,770
Amortization of deferred policy acquisition costs	646	610	700
Other operating expenses	1,135	1,062	950
Net written premiums (excluding life)	4,094	3,417	3,227
Property and Casualty Insurance [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs	221	211	204
Reserves for future policy benefits, claims and unpaid losses and LAE	7,872	6,410	6,845
Unearned premiums	1,956	1,757	1,651
Net earned premiums	3,878	3,204	2,847
Net investment income	294	263	275
Benefits, claims, losses and settlement expenses	2,494	2,040	1,873
Amortization of deferred policy acquisition costs	485	460	423
Other operating expenses	746	607	528
Net written premiums (excluding life)	4,020	3,341	2,949
Annuity [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs	564	723	299
Reserves for future policy benefits, claims and unpaid losses and LAE	23,764	20,944	17,609
Net investment income	1,136	1,034	976
Benefits, claims, losses and settlement expenses	648	531	541
Amortization of deferred policy acquisition costs	155	144	163
Other operating expenses	83	103	68
Run-off Long-term Care and Life [Member]
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs	36	41	47
Reserves for future policy benefits, claims and unpaid losses and LAE	2,175	2,008	2,059
Net earned premiums	108	114	119
Net investment income	82	76	69
Benefits, claims, losses and settlement expenses	164	160	225
Amortization of deferred policy acquisition costs	6	6	95
Other operating expenses	34	38	28
Net written premiums (excluding life)	74	76	79
Medicare Supplement and Critical Illness [Member]
Supplementary Insurance Information, by Segment [Line Items]
Net earned premiums			199
Net investment income			7
Benefits, claims, losses and settlement expenses			131
Amortization of deferred policy acquisition costs			19
Other operating expenses			34
Net written premiums (excluding life)			199
Other [Member]
Supplementary Insurance Information, by Segment [Line Items]
Net investment income	-11	-27	-26
Other operating expenses	$272	$314	$292