American Financial (AFG) 10-K 26 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Feb. 01, 2019	Jun. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	AMERICAN FINANCIAL GROUP INC
Entity Central Index Key	1,042,046
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Public Float			$ 8,400
Entity Common Stock, Shares Outstanding		89,312,398

Consolidated Balance Sheet

Consolidated Balance Sheet - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Assets:
Cash and cash equivalents	$ 1,515	$ 2,338
Investments:
Fixed maturities, available for sale at fair value (amortized cost — $41,837 and $37,038)	41,997	38,379
Fixed maturities, trading at fair value	105	348
Equity securities, at fair value	1,814	1,662
Investments accounted for using the equity method	1,374	999
Mortgage loans	1,068	1,125
Policy loans	174	184
Equity index call options	184	701
Real estate and other investments	267	312
Total cash and investments	48,498	46,048
Recoverables from reinsurers	3,349	3,369
Prepaid reinsurance premiums	610	600
Agents’ balances and premiums receivable	1,234	1,146
Deferred policy acquisition costs	1,682	1,216
Assets of managed investment entities	4,700	4,902
Other receivables	1,090	1,030
Variable annuity assets (separate accounts)	557	644
Other assets	1,529	1,504
Goodwill	207	199
Total assets	63,456	60,658
Liabilities and Equity:
Unpaid losses and loss adjustment expenses	9,741	9,678
Unearned premiums	2,595	2,410
Annuity benefits accumulated	36,616	33,316
Life, accident and health reserves	635	658
Payable to reinsurers	752	743
Liabilities of managed investment entities	4,512	4,687
Long-term debt	1,302	1,301
Variable annuity liabilities (separate accounts)	557	644
Other liabilities	1,774	1,887
Total liabilities	58,484	55,324
Redeemable noncontrolling interests	0	3
Shareholders’ equity:
Common Stock, no par value — 200,000,000 shares authorized — 89,291,724 and 88,275,460 shares outstanding	89	88
Capital surplus	1,245	1,181
Retained earnings	3,588	3,248
Accumulated other comprehensive income, net of tax	48	813
Total shareholders’ equity	4,970	5,330
Noncontrolling interests	2	1
Total equity	4,972	5,331
Total liabilities and equity	$ 63,456	$ 60,658

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Fixed maturities, available for sale at amortized cost	$ 41,837	$ 37,038
Common Stock, par value (USD per share)	$ 0	$ 0
Common Stock, shares authorized	200,000,000	200,000,000
Common Stock, shares outstanding	89,291,724	88,275,460

Consolidated Statement of Earni

Consolidated Statement of Earnings - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Property and casualty insurance net earned premiums	$ 4,865	$ 4,579	$ 4,328
Life, accident and health net earned premiums	24	22	24
Net investment income	2,094	1,831	1,696
Realized gains (losses) on:
Securities	(266)	5	19
Subsidiaries	0	0	2
Income (loss) of managed investment entities:
Investment income	255	210	190
Gain (loss) on change in fair value of assets/liabilities	(21)	12	15
Other income	199	206	224
Total revenues	7,150	6,865	6,498
Costs and Expenses:
Property and casualty insurance: Losses and loss adjustment expenses	3,003	2,955	2,762
Property and casualty insurance: Commissions and other underwriting expenses	1,583	1,407	1,349
Annuity benefits	998	892	800
Life, accident and health benefits	40	26	33
Annuity and supplemental insurance acquisition expenses	261	173	186
Interest charges on borrowed money	62	85	77
Expenses of managed investment entities	211	181	151
Other expenses	353	422	353
Total costs and expenses	6,511	6,141	5,711
Earnings before income taxes	639	724	787
Provision for income taxes	122	247	119
Net earnings, including noncontrolling interests	517	477	668
Less: Net earnings (losses) attributable to noncontrolling interests	(13)	2	19
Net Earnings Attributable to Shareholders	$ 530	$ 475	$ 649
Earnings Attributable to Shareholders per Common Share:
Basic (USD per share)	$ 5.95	$ 5.40	$ 7.47
Diluted (USD per share)	$ 5.85	$ 5.28	$ 7.33
Average number of Common Shares:
Basic (shares)	89	87.8	86.9
Diluted (shares)	90.6	89.8	88.5
Supplemental disclosure of Realized gains (losses) on securities:
Realized gains (losses) before impairments	$ (247)	$ 78	$ 135
Losses on securities with impairment	(19)	(74)	(115)
Non-credit portion recognized in other comprehensive income (loss)	0	1	(1)
Impairment charges recognized in earnings	(19)	(73)	(116)
Total realized gains (losses) on securities	$ (266)	$ 5	$ 19

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net earnings, including noncontrolling interests	$ 517	$ 477	$ 668
Net unrealized gains (losses) on securities:
Unrealized holding gains (losses) on securities arising during the period	(544)	297	80
Reclassification adjustment for realized (gains) losses included in net earnings	8	(10)	(12)
Total net unrealized gains (losses) on securities	(536)	287	68
Net unrealized gains (losses) on cash flow hedges	2	(4)	(8)
Foreign currency translation adjustments	(10)	12	7
Pension and other postretirement plans adjustments	0	1	0
Other comprehensive income (loss), net of tax	(544)	296	67
Total comprehensive income (loss), net of tax	(27)	773	735
Less: Comprehensive income (loss) attributable to noncontrolling interests	(13)	2	24
Comprehensive income (loss) attributable to shareholders	$ (14)	$ 771	$ 711

Consolidated Statement of Chang

Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Total	Common Shares	Common Stock and Capital Surplus	Retained Earnings	Accumulated Other Comprehensive Inc. (Loss)		Noncontrolling Interests
Beginning Balance, shares at Dec. 31, 2015			87,474,452
Beginning Balance at Dec. 31, 2015	$ 4,770	$ 4,592		$ 1,301	$ 2,987	$ 304		$ 178
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to parent	649	649			649
Net income (loss), including portion attributable to nonredeemable noncontrolling interest	668							19
Other comprehensive income (loss)	67	62				62		5
Dividends	(187)	(187)			(187)
Shares issued:
Exercise of stock options, shares			958,344
Exercise of stock options	32	32		32
Restricted stock awards, shares			318,940
Restricted stock awards	0	0		0
Other benefit plans, shares			95,875
Other benefit plans	7	7		7
Dividend reinvestment plan, shares			25,516
Dividend reinvestment plan	2	2		2
Stock-based compensation: Expense	22	22		22
Shares acquired and retired, shares			(1,911,976)
Shares acquired and retired	(133)	(133)		(29)	(104)
Shares exchanged — benefit plans, shares			(32,707)
Shares exchanged — benefit plans	(2)	(2)		0	(2)
Forfeitures of restricted stock, shares			(4,045)
Forfeitures of restricted stock	0	0		0
Acquisition of noncontrolling interests	(315)	(128)		(137)		9	[1]	(187)
Other	(12)				0			(12)
Ending Balance, shares at Dec. 31, 2016			86,924,399
Ending Balance at Dec. 31, 2016	4,919	4,916		1,198	3,343	375		3
Beginning Balance, Redeemable Noncontrolling Interests at Dec. 31, 2015	0
Ending Balance, Redeemable Noncontrolling Interests at Dec. 31, 2016	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) attributable to parent	475	475			475
Net income (loss), including portion attributable to nonredeemable noncontrolling interest	477							2
Other comprehensive income (loss)	296	296				296		0
Impact of the U.S. corporate tax rate change on AOCI	0	0			(145)	145		0
Dividends	(421)	(421)			(421)
Shares issued:
Exercise of stock options, shares			1,020,986
Exercise of stock options	34	34		34
Restricted stock awards, shares			232,250
Restricted stock awards	0	0		0
Other benefit plans, shares			99,588
Other benefit plans	10	10		10
Dividend reinvestment plan, shares			42,572
Dividend reinvestment plan	4	4		4
Stock-based compensation: Expense	24	24		24
Shares exchanged — benefit plans, shares			(37,718)
Shares exchanged — benefit plans	(5)	(5)		(1)	(4)
Forfeitures of restricted stock, shares			(6,617)
Forfeitures of restricted stock	0	0		0
Sale of redeemable noncontrolling interests	(3)	(3)				(3)		0
Other	$ (4)	0			0	0		(4)
Ending Balance, shares at Dec. 31, 2017	88,275,460		88,275,460
Ending Balance at Dec. 31, 2017	$ 5,331	5,330		1,269	3,248	813		1
Ending Balance, Redeemable Noncontrolling Interests at Dec. 31, 2017	3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change	4	4			225	(221)
Redeemable Noncontrolling Interest, Equity, Carrying Amount [Abstract]
Redeemable noncontrolling interests	3
Net income (loss) attributable to parent	530	530			530
Net income (loss), including portion attributable to nonredeemable noncontrolling interest	531							1
Other comprehensive income (loss)	(544)	(544)				(544)		0
Dividends	$ (397)	(397)			(397)
Exercise of stock options, shares	778,270		778,270
Exercise of stock options	$ 29	29		29
Restricted stock awards, shares			200,625
Restricted stock awards	0	0		0
Other benefit plans, shares			103,797
Other benefit plans	12	12		12
Dividend reinvestment plan, shares			29,998
Dividend reinvestment plan	3	3		3
Stock-based compensation: Expense	23	23		23
Shares acquired and retired, shares			(65,589)
Shares acquired and retired	(6)	(6)		(1)	(5)
Shares exchanged — benefit plans, shares			(26,520)
Shares exchanged — benefit plans	(3)	(3)		(1)	(2)
Forfeitures of restricted stock, shares			(4,317)
Forfeitures of restricted stock	0	0		0
Other	$ (11)	(11)			(11)			0
Ending Balance, shares at Dec. 31, 2018	89,291,724		89,291,724
Ending Balance at Dec. 31, 2018	$ 4,972	$ 4,970		$ 1,334	$ 3,588	$ 48		$ 2
Redeemable Noncontrolling Interest, Equity, Carrying Amount [Abstract]
Net income (loss) attributable to redeemable noncontrolling interest	(14)
Shareholders' equity, redeemable noncontrolling interests, other changes	11
Ending Balance, Redeemable Noncontrolling Interests at Dec. 31, 2018	0
Redeemable Noncontrolling Interest, Equity, Carrying Amount [Abstract]
Redeemable noncontrolling interests	$ 0
[1]	On January 1, 2018, AFG adopted new guidance that requires all equity securities other than those accounted for under the equity method to be reported at fair value with holding gains and losses recognized in net earnings. At the date of adoption, the $221 million net unrealized gain on equity securities classified as available for sale (with unrealized holding gains and losses reported in AOCI) under the prior guidance was reclassified from AOCI to retained earnings as the cumulative effect of an accounting change. Other also includes the December 2017 reclassification of $145 million stranded in AOCI from accounting for the Tax Cuts and Jobs Act of 2017 to retained earnings (see Note A — “Accounting Policies — Income Taxes”), the impact on AOCI of the December 2017 sale of redeemable noncontrolling interests in Neon and the November 2016 acquisition of the noncontrolling interest in NATL (see Note B — “Acquisitions and Sale of Businesses”).

Consolidated Statement of Cha_2

Consolidated Statement of Changes in Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Stockholders' Equity [Abstract]
Cash dividends per Common Share (USD per share)	$ 4.45	$ 4.7875	$ 2.1525

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities:
Net earnings, including noncontrolling interests	$ 517	$ 477	$ 668
Adjustments:
Depreciation and amortization	210	107	134
Annuity benefits	998	892	800
Realized (gains) losses on investing activities	265	(23)	(61)
Net sales of trading securities	111	17	79
Deferred annuity and life policy acquisition costs	(263)	(225)	(230)
Change in:
Reinsurance and other receivables	(211)	(963)	(315)
Other assets	96	13	(467)
Insurance claims and reserves	425	1,321	533
Payable to reinsurers	9	109	43
Other liabilities	(140)	(18)	265
Managed investment entities’ assets/liabilities	148	60	(279)
Other operating activities, net	(82)	37	(20)
Net cash provided by operating activities	2,083	1,804	1,150
Investing Activities:
Purchases of fixed maturities	(10,183)	(9,485)	(7,537)
Purchases of equity securities	(568)	(182)	(207)
Purchases of mortgage loans	(167)	(254)	(341)
Purchases of equity index call options and other investments	(973)	(831)	(738)
Purchases of real estate, property and equipment	(80)	(109)	(49)
Purchases of businesses	(36)	0	0
Proceeds from maturities and redemptions of fixed maturities	4,948	6,105	4,713
Proceeds from repayments of mortgage loans	201	215	262
Proceeds from sales of fixed maturities	501	392	641
Proceeds from sales of equity securities	247	216	348
Proceeds from sales and settlements of equity index call options and other investments	883	789	319
Proceeds from sales of real estate, property and equipment	3	55	55
Cash and cash equivalents of businesses acquired	13	0	0
Managed investment entities:
Purchases of investments	(2,117)	(2,979)	(2,254)
Proceeds from sales and redemptions of investments	1,948	2,774	1,890
Other investing activities, net	30	2	(83)
Net cash used in investing activities	(5,350)	(3,292)	(2,981)
Financing Activities:
Annuity receipts	5,632	4,341	4,585
Annuity surrenders, benefits and withdrawals	(2,916)	(2,405)	(2,275)
Net transfers from variable annuity assets	47	54	42
Additional long-term borrowings	0	712	302
Reductions of long-term debt	0	(745)	(18)
Issuances of managed investment entities’ liabilities	1,983	2,731	2,293
Retirements of managed investment entities’ liabilities	(1,935)	(2,585)	(1,600)
Issuances of Common Stock	33	37	35
Repurchases of Common Stock	(6)	0	(133)
Cash dividends paid on Common Stock	(394)	(417)	(185)
Acquisition of noncontrolling interests in subsidiary	0	0	(315)
Other financing activities, net	0	(4)	(13)
Net cash provided by (used in) financing activities	2,444	1,719	2,718
Net Change in Cash and Cash Equivalents	(823)	231	887
Cash and cash equivalents at beginning of year	2,338	2,107	1,220
Cash and cash equivalents at end of year	$ 1,515	$ 2,338	$ 2,107

Accounting Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Accounting Policies	Accounting Policies Basis of Presentation The consolidated financial statements include the accounts of American Financial Group, Inc. and its subsidiaries (“AFG”). 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, 2018 , 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. AFG did not have any significant nonrecurring fair value measurements of nonfinancial assets and liabilities in 2018 or 2017 . Investments On January 1, 2018, AFG adopted Accounting Standards Update (“ASU”) 2016-01, which requires all equity securities other than those accounted for under the equity method to be reported at fair value with holding gains and losses recognized in net earnings. At December 31, 2017, AFG had $1.60 billion in equity securities classified as “available for sale” under the prior guidance with holding gains and losses included in accumulated other comprehensive income (“AOCI”) instead of net earnings. At the date of adoption, the $221 million net unrealized gain on equity securities included in AOCI was reclassified to retained earnings as the cumulative effect of an accounting change. The cumulative effect of the accounting change also includes the net unrealized gain on AFG’s small number of limited partnerships and similar investments carried at cost under the prior guidance that are carried at fair value through net earnings under the new guidance ( $4 million net of tax at the date of adoption). Holding gains and losses on equity securities carried at fair value under ASU 2016-01 are generally recorded in realized gains (losses) on securities. However, prior to the adoption of the new guidance, AFG classified a small portion of its equity securities as “trading” and reported those investments at fair value with holding gains and losses recognized in net investment income. These investments consisted primarily of equity securities held to offset the impact of changes in the stock market on employee benefit plans that are impacted by stock market performance and totaled $62 million at December 31, 2017. Following the adoption of the new guidance, AFG continues to record holding gains and losses on these securities, as well as its small portfolio of limited partnerships and similar investments carried at fair value under the new guidance and certain other securities classified at purchase as “fair value through net investment income” in net investment income. Under the new guidance, AFG recorded holding losses of $257 million on equity securities in net earnings during 2018 on securities that were still owned at December 31, 2018 . Under the prior guidance, these holding losses would have been recorded in AOCI (with the exception of any impairment charge that may have been recorded). Because almost all of the equity securities impacted by the new guidance were carried at fair value through AOCI under the prior guidance, the adoption of the new guidance did not have a material impact on AFG’s financial position. Fixed maturity securities classified as “available for sale” are reported at fair value with unrealized gains and losses included in AOCI in AFG’s Balance Sheet. Fixed maturity 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 effective 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. Limited partnerships and similar investments are generally accounted for using the equity method of accounting. Under the equity method, AFG records its share of the earnings or losses of the investee based on when they are reported by the investee in its financial statements rather than in the period in which the investee declares a dividend. AFG’s share of the earnings or losses from equity method investments is generally recorded on a quarter lag due to the timing of the receipt of the investee’s financial statements. AFG’s equity in the earnings (losses) of limited partnerships and similar investments is included in net investment income. Gains or losses on fixed-maturity 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 and qualify as highly effective 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 and principal-only MBS) and (ii) the equity-based component of certain annuity products (included in annuity benefits accumulated) and related equity index options 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 impacts 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 statement of earnings as the cash flows from the hedged item. AFG uses interest rate swaps that are designated and qualify as highly effective cash flow hedges to mitigate interest rate risk related to certain floating-rate securities included in AFG’s portfolio of fixed maturity securities. For derivatives that are designated and qualify as highly effective fair value hedges, changes in the fair value of the derivative, along with changes in the fair value of the hedged item attributable to the hedged risk, are recognized in current period earnings. 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. An AFG 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 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 ” ). 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) through its investment in the CLO debt tranches, it has exposure to CLO losses (limited to the amount AFG invested) and the right to receive CLO benefits that 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. 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 net gain or loss from accounting for the CLO assets and liabilities at fair value is presented separately in AFG’s Statement of Earnings. The fair values of a CLO’s assets may differ from the separately measured fair values of its liabilities even though the CLO liabilities only have recourse to the CLO assets. AFG has 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 a separately measured fair value. CLO earnings attributable to AFG’s shareholders are measured by the change in the fair value of AFG’s investments in the CLOs and management fees earned. 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 annuity benefits expense and decreases for annuity policy charges are recorded in other income. For traditional fixed annuities, the liability for annuity benefits accumulated represents the account value that had accrued to the benefit of the policyholder as of the balance sheet date. For fixed-indexed annuities, the liability for annuity benefits accumulated includes an embedded derivative that represents the estimated fair value of the index participation with the remaining component representing the discounted value of the guaranteed minimum contract benefits. 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 (included in other income) 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 (losses) 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. Debt Issuance Costs Debt issuance costs related to AFG’s outstanding debt are presented in its Balance Sheet as a direct reduction in the carrying value of long-term debt and are amortized over the life of the related debt using the effective interest method as a component of interest expense. Debt issuance costs related to AFG’s revolving credit facilities are included in other assets 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 represent 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. Noncontrolling interests that are redeemable at the option of the holder are presented separately in the mezzanine section of the balance sheet (between liabilities and equity). 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. The effect of a change in tax rates on deferred tax assets and liabilities is recorded in net earnings in the period that includes the enactment date. This includes the impact on deferred tax assets or liabilities established through AOCI, which results in an amount equal to the difference between the deferred tax at the historical corporate rate and the newly enacted rate stranded in AOCI. As permitted under guidance adopted effective December 31, 2017 (ASU 2018-02), AFG reclassified the $145 million stranded in AOCI from accounting for the Tax Cuts and Jobs Act of 2017 to retained earnings at December 31, 2017. See Note L — “ Income Taxes ” for further information. 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: 2018 – 1.6 million , 2017 – 2.0 million and 2016 – 1.6 million . AFG’s weighted average diluted shares outstanding excludes the following anti-dilutive potential common shares related to stock compensation plans: 2018 and 2017 – none and 2016 – 0.4 million . Adjustments to net earnings attributable to shareholders in the calculation of diluted earnings per share were nominal in the 2018 , 2017 and 2016 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, property and equipment and businesses. “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. Revenue Recognition Guidance Effective in 2018 On January 1, 2018, AFG adopted ASU 2014-09, which provides guidance on recognizing revenue when (or as) performance obligations under the contract are satisfied. The new guidance also updates the accounting for certain costs associated with obtaining and fulfilling contracts with customers and requires certain new disclosures. Because revenue recognition for insurance contracts and financial instruments (AFG’s primary sources of revenue) were excluded from the scope of the new guidance, the adoption of ASU 2014-09 did not have a material impact on AFG’s results of operations and financial position. Lease Accounting Guidance Effective in 2019 In February 2016, the FASB issued ASU 2016-02, which requires entities that lease assets for terms longer than one year to recognize the assets and liabilities for the rights and obligations created by those leases on the balance sheet based on the present value of contractual cash flows. Qualitative and quantitative disclosures of the amount, timing and uncertainty of cash flows arising from leases will also be required. AFG will adopt the updated guidance effective January 1, 2019. The new guidance will not have a material effect on AFG’s results of operations because it does not change the manner in which lease-related expenses are recognized in the statement of earnings. In addition, the new guidance will not have a material effect on AFG’s financial position as recognizing the assets and liabilities related to operating leases upon adoption of the new guidance in January 2019 will increase AFG’s consolidated assets and consolidated liabilities by less than one-half of 1% as compared to AFG’s Balance Sheet at December 31, 2018.

Acquisitions and Sale of Busine

Acquisitions and Sale of Businesses	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Acquisitions and Sale of Businesses	Acquisitions and Sale of Businesses ABA Insurance Services Inc. In November 2018, AFG acquired ABA Insurance Services Inc. (“ABAIS”) from American Bankers Mutual Insurance, Ltd. for approximately $30 million using cash on hand at the parent company. Additional contingent consideration of up to $3 million could be due after four years based on achieving certain operating milestones. ABAIS is based in Ohio and is a market-leading provider of directors and officers liability and other complementary insurance solutions for banks, small businesses and nonprofit organizations. The allocation of the purchase price is shown in the table below (in millions): November 30, Total purchase price $ 30 Tangible assets acquired 28 Liabilities acquired 26 Net tangible assets acquired, at fair value 2 Excess purchase price over net tangible assets acquired $ 28 Allocation of excess purchase price: Intangible assets acquired (*) $ 25 Deferred tax on intangible assets acquired (*) (5 ) Goodwill 8 $ 28 (*) Included in Other assets in AFG’s Balance Sheet. Approximately $25 million of the purchase price was recorded as a finite lived customer relationship intangible asset, which will be amortized over its estimated life of 9 years . The fair value of this intangible was estimated using a multi-period excess earnings method, which is a form of the income approach. The acquisition resulted in the recognition of $8 million in 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 ABAIS’s assembled workforce. Business generated by ABAIS is included in the Specialty casualty sub-segment. Neon Lloyd’s Business On December 29, 2017, AFG completed the sale of an indirect noncontrolling interest in Neon, its United Kingdom-based Lloyd’s insurer, to certain Neon executives for cash equal to the fair value of the interest sold as determined by a third-party valuation firm. Because AFG continues to have a controlling interest in Neon, the sale was accounted for as an equity transaction with the excess of the carrying value of the net assets attributable to the noncontrolling interest sold over the consideration received recorded as a $3 million reduction in AFG’s Capital Surplus. As discussed in Note L — “ Income Taxes ,” the sale of the noncontrolling interest also resulted in the recognition of a $56 million tax benefit, including a $48 million tax benefit previously deferred in the 2016 restructuring of the Neon Lloyd’s operations. Acquisition of Noncontrolling Interest in National Interstate Corporation On November 10, 2016, AFG acquired the 49% of National Interstate Corporation (“NATL”) not previously owned by AFG’s wholly-owned subsidiary, Great American Insurance Company for $315 million ( $32.00 per share) in a merger transaction. In addition, NATL paid a one-time special cash dividend of $0.50 per share to its shareholders immediately prior to the merger closing ( $5 million was paid to noncontrolling shareholders). Expenses related to the merger were approximately $10 million and were expensed as incurred. Because NATL was already a consolidated subsidiary of AFG prior to the merger, the acquisition was accounted for as an equity transaction. As a result, the excess of the consideration paid over the carrying value of the noncontrolling interest acquired was recorded as a $137 million reduction in AFG’s Capital Surplus. In addition, the merger allowed NATL and its subsidiaries to become members of the AFG consolidated tax group, which resulted in a tax benefit of $66 million in the fourth quarter of 2016.

Segments of Operations

Segments of Operations	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Segments of Operations	Segments of Operations AFG manages its business as three segments: (i) Property and casualty insurance, (ii) Annuity and (iii) Other, which includes holding company assets and costs, revenues and costs of AFG’s limited insurance operations outside of property and casualty insurance and annuities, 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 equipment leasing and 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, fixed-indexed and variable-indexed annuities in the retail, financial institutions, registered investment advisor and education markets. AFG’s reportable segments and their components were determined based primarily upon similar economic characteristics, products and services. Effective January 1, 2018, the results of AFG’s run-off long-term care and life businesses are included in the “Other” segment instead of as a separate reportable segment based on the immaterial size of the remaining operations. Prior period amounts were reclassified for consistent presentation. Sales of property and casualty insurance outside of the United States represented 7% of AFG’s revenues in 2018 , 5% of AFG’s revenues in 2017 and 4% of AFG’s revenues in 2016 . The following tables (in millions) show AFG’s assets, revenues and earnings before income taxes by segment and sub-segment. 2018 2017 2016 Assets Property and casualty insurance (a) $ 17,681 $ 17,171 $ 15,574 Annuity 39,952 37,179 33,409 Other 5,823 6,308 6,089 Total assets $ 63,456 $ 60,658 $ 55,072 Revenues Property and casualty insurance: Premiums earned: Specialty Property and transportation $ 1,729 $ 1,711 $ 1,662 Specialty casualty 2,403 2,186 2,006 Specialty financial 598 576 557 Other specialty 135 106 103 Total premiums earned 4,865 4,579 4,328 Net investment income 438 362 350 Other income (b) 10 28 51 Total property and casualty insurance 5,313 4,969 4,729 Annuity: Net investment income 1,638 1,458 1,356 Other income 107 103 103 Total annuity 1,745 1,561 1,459 Other 358 330 289 Total revenues before realized gains (losses) 7,416 6,860 6,477 Realized gains (losses) on securities (266 ) 5 19 Realized gains on subsidiaries — — 2 Total revenues $ 7,150 $ 6,865 $ 6,498 (a) Not allocable to sub-segments. (b) Includes income of $32 million (before noncontrolling interest) from the sale of an apartment property in 2016. 2018 2017 2016 Earnings Before Income Taxes Property and casualty insurance: Underwriting: Specialty Property and transportation $ 120 $ 154 $ 166 Specialty casualty 141 104 78 Specialty financial 66 61 84 Other specialty (5 ) (2 ) 9 Other lines (a) (20 ) (75 ) (101 ) Total underwriting 302 242 236 Investment and other income, net (b) 407 349 341 Total property and casualty insurance 709 591 577 Annuity 361 380 368 Other (c) (165 ) (252 ) (179 ) Total earnings before realized gains (losses) and income taxes 905 719 766 Realized gains (losses) on securities (266 ) 5 19 Realized gains on subsidiaries — — 2 Total earnings before income taxes $ 639 $ 724 $ 787 (a) Includes special charges to increase asbestos and environmental (“A&E”) reserves of $18 million , $89 million and $36 million in 2018 , 2017 and 2016 , respectively. Also includes $18 million in favorable development related to the Neon exited lines recorded in connection with a reinsurance to close transaction in 2017 and a charge of $65 million related to Neon exited lines in 2016. (b) Includes income of $32 million (before noncontrolling interest) from the sale of an apartment property in 2016. (c) Primarily holding company interest and expenses, including losses on retirement of debt of $51 million in 2017 and special charges to increase A&E reserves related to AFG’s former railroad and manufacturing operations ( $9 million in 2018 , $24 million in 2017 and $5 million in 2016 ).

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2018
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, 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, asset-backed securities (“ABS”), mortgage-backed securities (“MBS”), non-affiliated common stocks, equity index options 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 at the valuation date. AFG’s Level 3 is comprised of financial instruments 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. As discussed in Note A — “ Accounting Policies — Managed Investment Entities ,” AFG has set the carrying value of its 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 separately measured fair values. As a result, the CLO liabilities are categorized within the fair value hierarchy on the same basis (proportionally) as the related CLO assets. Since the portion of the CLO liabilities allocated to Level 3 is derived from the fair value of the CLO assets, these amounts are excluded from the progression of Level 3 financial instruments. 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 25 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 services 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 December 31, 2018 Assets: Available for sale (“AFS”) fixed maturities: U.S. Government and government agencies $ 141 $ 83 $ 9 $ 233 States, municipalities and political subdivisions — 6,880 59 6,939 Foreign government — 142 — 142 Residential MBS — 2,547 197 2,744 Commercial MBS — 864 56 920 Asset-backed securities — 8,964 847 9,811 Corporate and other 28 19,184 1,996 21,208 Total AFS fixed maturities 169 38,664 3,164 41,997 Trading fixed maturities 9 96 — 105 Equity securities 1,410 68 336 1,814 Equity index call options — 184 — 184 Assets of managed investment entities (“MIE”) 203 4,476 21 4,700 Variable annuity assets (separate accounts) (*) — 557 — 557 Other assets — derivatives — 16 — 16 Total assets accounted for at fair value $ 1,791 $ 44,061 $ 3,521 $ 49,373 Liabilities: Liabilities of managed investment entities $ 195 $ 4,297 $ 20 $ 4,512 Derivatives in annuity benefits accumulated — — 2,720 2,720 Other liabilities — derivatives — 49 — 49 Total liabilities accounted for at fair value $ 195 $ 4,346 $ 2,740 $ 7,281 December 31, 2017 Assets: Available for sale fixed maturities: U.S. Government and government agencies $ 122 $ 112 $ 8 $ 242 States, municipalities and political subdivisions — 6,975 148 7,123 Foreign government — 127 — 127 Residential MBS — 3,105 122 3,227 Commercial MBS — 926 36 962 Asset-backed securities — 7,218 744 7,962 Corporate and other 30 17,662 1,044 18,736 Total AFS fixed maturities 152 36,125 2,102 38,379 Trading fixed maturities 44 304 — 348 Equity securities 1,411 86 165 1,662 Equity index call options — 701 — 701 Assets of managed investment entities 307 4,572 23 4,902 Variable annuity assets (separate accounts) (*) — 644 — 644 Other assets — derivatives — — — — Total assets accounted for at fair value $ 1,914 $ 42,432 $ 2,290 $ 46,636 Liabilities: Liabilities of managed investment entities $ 293 $ 4,372 $ 22 $ 4,687 Derivatives in annuity benefits accumulated — — 2,542 2,542 Other liabilities — derivatives — 35 — 35 Total liabilities accounted for at fair value $ 293 $ 4,407 $ 2,564 $ 7,264 (*) 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, 2018 , 2017 and 2016 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 2018 2017 2016 2018 2017 2016 2018 2017 2016 2018 2017 2016 Perpetual preferred stocks 2 4 6 $ 5 $ 23 $ 35 2 2 7 $ 6 $ 11 $ 28 Common stocks — — 3 — — — — 1 2 — — — Transfers between Level 1 and Level 2 for all periods presented were a result of increases or decreases in observable trade activity. Approximately 7% of the total assets carried at fair value on December 31, 2018 , were Level 3 assets. Approximately 69% ( $2.41 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. Internally developed Level 3 asset fair values represent approximately $1.05 billion at December 31, 2018 . Of this amount, approximately $590 million relates to fixed maturity securities that were priced using management’s best estimate of an appropriate credit spread over the treasury yield (of a similar duration) to discount future expected cash flows using a third party model. The credit spread applied by management is the significant unobservable input. For this group of approximately 100 securities, the average spread used was 585 basis points over the reference treasury yield and the spreads ranged from 131 basis points to 2,966 basis points (approximately 80% of the spreads were between 400 and 700 basis points). Had management used higher spreads, the fair value of this group of securities would have been lower. Conversely, if the spreads used were lower, the fair values would have been higher. For the remainder of the internally developed prices, any justifiable changes in unobservable inputs used to determine fair value would not have resulted in a material change in AFG’s financial position. The derivatives embedded in AFG’s fixed-indexed and variable-indexed annuity liabilities are measured using a discounted cash flow approach and had a fair value of $2.72 billion at December 31, 2018 . The following table presents information about the unobservable inputs used by management in determining fair value of these Level 3 liabilities. See Note F — “ Derivatives .” Unobservable Input Range Adjustment for insurance subsidiary’s credit risk 0.6% – 2.1% over the risk free rate Risk margin for uncertainty in cash flows 0.73% reduction in the discount rate Surrenders 3% – 23% of indexed account value Partial surrenders 2% – 9% of indexed account value Annuitizations 0.1% – 1% of indexed account value Deaths 1.5% – 9.5% of indexed account value Budgeted option costs 2.6% – 3.6% of indexed account value The range of adjustments for insurance subsidiary’s credit risk is based on the Moody’s corporate A2 bond index and 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 and variable-indexed annuity products with an expected range of 7% to 11% in the majority of future calendar years ( 3% to 23% over all periods). Increasing the budgeted option cost or risk margin for uncertainty in cash flow assumptions in the table above would increase the fair value of the fixed-indexed and variable-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 2018 , 2017 and 2016 are presented below (in millions). The transfers into and out of Level 3 were due to changes in the availability of market observable inputs and $29 million of equity securities transferred into Level 3 in the first quarter of 2018 related to a small number of limited partnerships and similar investments carried at cost under the prior guidance that are carried at fair value through net earnings under new guidance adopted on January 1, 2018, as discussed in Note A — “ Accounting Policies — Investments .” 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, 2017 Net earnings Other comprehensive income (loss) Purchases and issuances Sales and settlements Transfer into Level 3 Transfer out of Level 3 Balance at December 31, 2018 AFS fixed maturities: U.S. government agency $ 8 $ — $ — $ — $ — $ 1 $ — $ 9 State and municipal 148 — (2 ) — (3 ) — (84 ) 59 Residential MBS 122 (9 ) (4 ) — (21 ) 130 (21 ) 197 Commercial MBS 36 — — 20 — — — 56 Asset-backed securities 744 (3 ) (15 ) 426 (248 ) 82 (139 ) 847 Corporate and other 1,044 (10 ) (18 ) 1,221 (204 ) 27 (64 ) 1,996 Total AFS fixed maturities 2,102 (22 ) (39 ) 1,667 (476 ) 240 (308 ) 3,164 Equity securities 165 9 — 155 (6 ) 30 (17 ) 336 Assets of MIE 23 (8 ) — 6 — — — 21 Total Level 3 assets $ 2,290 $ (21 ) $ (39 ) $ 1,828 $ (482 ) $ 270 $ (325 ) $ 3,521 Embedded derivatives (a) $ (2,542 ) $ 204 $ — $ (545 ) $ 163 $ — $ — $ (2,720 ) Total Level 3 liabilities (b) $ (2,542 ) $ 204 $ — $ (545 ) $ 163 $ — $ — $ (2,720 ) (a) Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $44 million in 2018 . (b) As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets. Total realized/unrealized Balance at December 31, 2016 Net Other Purchases Sales and Transfer Transfer Balance at December 31, 2017 AFS fixed maturities: U.S. government agency $ 8 $ — $ — $ — $ — $ — $ — $ 8 State and municipal 140 — 2 — (2 ) 10 (2 ) 148 Residential MBS 190 (4 ) 2 1 (40 ) 44 (71 ) 122 Commercial MBS 25 2 — 15 (10 ) 4 — 36 Asset-backed securities 484 — 1 410 (132 ) 202 (221 ) 744 Corporate and other 712 (5 ) 2 606 (237 ) 29 (63 ) 1,044 Total AFS fixed maturities 1,559 (7 ) 7 1,032 (421 ) 289 (357 ) 2,102 Equity securities 174 (21 ) 10 38 (16 ) — (20 ) 165 Assets of MIE 29 (11 ) — 9 — — (4 ) 23 Total Level 3 assets $ 1,762 $ (39 ) $ 17 $ 1,079 $ (437 ) $ 289 $ (381 ) $ 2,290 Embedded derivatives (a) $ (1,759 ) $ (589 ) $ — $ (300 ) $ 106 $ — $ — $ (2,542 ) Total Level 3 liabilities (b) $ (1,759 ) $ (589 ) $ — $ (300 ) $ 106 $ — $ — $ (2,542 ) (a) Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $25 million in 2017 . (b) As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets. Total realized/unrealized gains (losses) included in Balance at December 31, 2015 Net earnings Other comprehensive income (loss) Purchases and issuances Sales and settlements Transfer into Level 3 Transfer out of Level 3 Balance at December 31, 2016 AFS fixed maturities: U.S. government agency $ 15 $ (8 ) $ 1 $ — $ — $ — $ — $ 8 State and municipal 89 — (4 ) 57 (2 ) — — 140 Residential MBS 224 (4 ) (2 ) 8 (28 ) 34 (42 ) 190 Commercial MBS 39 (1 ) — — (7 ) — (6 ) 25 Asset-backed securities 470 (1 ) 1 50 (52 ) 60 (44 ) 484 Corporate and other 633 — (10 ) 176 (100 ) 30 (17 ) 712 Total AFS fixed maturities 1,470 (14 ) (14 ) 291 (189 ) 124 (109 ) 1,559 Equity securities 140 (12 ) 35 44 (28 ) 15 (20 ) 174 Assets of MIE 26 (9 ) — 12 — — — 29 Total Level 3 assets $ 1,636 $ (35 ) $ 21 $ 347 $ (217 ) $ 139 $ (129 ) $ 1,762 Embedded derivatives (a) $ (1,369 ) $ (211 ) $ — $ (277 ) $ 98 $ — $ — $ (1,759 ) Total Level 3 liabilities (b) $ (1,369 ) $ (211 ) $ — $ (277 ) $ 98 $ — $ — $ (1,759 ) (a) Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $17 million in 2016 . (b) As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets. 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 Value Value Total Level 1 Level 2 Level 3 2018 Financial assets: Cash and cash equivalents $ 1,515 $ 1,515 $ 1,515 $ — $ — Mortgage loans 1,068 1,056 — — 1,056 Policy loans 174 174 — — 174 Total financial assets not accounted for at fair value $ 2,757 $ 2,745 $ 1,515 $ — $ 1,230 Financial liabilities: Annuity benefits accumulated (*) $ 36,384 $ 34,765 $ — $ — $ 34,765 Long-term debt 1,302 1,231 — 1,228 3 Total financial liabilities not accounted for at fair value $ 37,686 $ 35,996 $ — $ 1,228 $ 34,768 2017 Financial assets: Cash and cash equivalents $ 2,338 $ 2,338 $ 2,338 $ — $ — Mortgage loans 1,125 1,119 — — 1,119 Policy loans 184 184 — — 184 Total financial assets not accounted for at fair value $ 3,647 $ 3,641 $ 2,338 $ — $ 1,303 Financial liabilities: Annuity benefits accumulated (*) $ 33,110 $ 32,461 $ — $ — $ 32,461 Long-term debt 1,301 1,354 — 1,351 3 Total financial liabilities not accounted for at fair value $ 34,411 $ 33,815 $ — $ 1,351 $ 32,464 (*) Excludes $232 million and $206 million of life contingent annuities in the payout phase at December 31, 2018 and 2017 , respectively. 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, 2018
Investments, Debt and Equity Securities [Abstract]
Investments	Investments Available for sale fixed maturities at December 31 consisted of the following (in millions): 2018 2017 Amortized Cost Gross Unrealized Net Unrealized Fair Value Amortized Cost Gross Unrealized Net Unrealized Fair Value Gains Losses Gains Losses Fixed maturities: U.S. Government and government agencies $ 235 $ 1 $ (3 ) $ (2 ) $ 233 $ 244 $ 1 $ (3 ) $ (2 ) $ 242 States, municipalities and political subdivisions 6,825 169 (55 ) 114 6,939 6,887 254 (18 ) 236 7,123 Foreign government 140 2 — 2 142 124 3 — 3 127 Residential MBS 2,476 277 (9 ) 268 2,744 2,884 349 (6 ) 343 3,227 Commercial MBS 905 17 (2 ) 15 920 927 36 (1 ) 35 962 Asset-backed securities 9,781 130 (100 ) 30 9,811 7,836 142 (16 ) 126 7,962 Corporate and other 21,475 167 (434 ) (267 ) 21,208 18,136 638 (38 ) 600 18,736 Total fixed maturities $ 41,837 $ 763 $ (603 ) $ 160 $ 41,997 $ 37,038 $ 1,423 $ (82 ) $ 1,341 $ 38,379 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, 2018 and December 31, 2017 , respectively, were $140 million and $158 million . Gross unrealized gains on such securities at December 31, 2018 and December 31, 2017 were $119 million and $137 million , respectively. Gross unrealized losses on such securities at both December 31, 2018 and December 31, 2017 were $4 million . These amounts represent the non-credit other-than-temporary impairment charges recorded in AOCI adjusted for subsequent changes in fair values and relate primarily to residential MBS. As discussed in Note A — “ Accounting Policies — Investments ,” AFG implemented new accounting guidance effective on January 1, 2018, which requires all equity securities previously classified as “available for sale” to be reported at fair value, with holding gains and losses recognized in net earnings. Equity securities reported at fair value consisted of the following at December 31, 2018 (in millions): Fair Value over (under) Actual Cost Fair Value Cost Common stocks $ 1,241 $ 1,148 $ (93 ) Perpetual preferred stocks 705 666 (39 ) Total equity securities carried at fair value $ 1,946 $ 1,814 $ (132 ) The following tables show gross unrealized losses (dollars in millions) on available for sale fixed maturities and equity securities by investment category and length of time that individual securities have been in a continuous unrealized loss position at the following balance sheet dates. Less Than Twelve Months Twelve Months or More Unrealized Loss Fair Value Fair Value as % of Cost Unrealized Loss Fair Value Fair Value as % of Cost December 31, 2018 Fixed maturities: U.S. Government and government agencies $ — $ 41 100 % $ (3 ) $ 120 98 % States, municipalities and political subdivisions (23 ) 1,497 98 % (32 ) 902 97 % Foreign government — 18 100 % — 4 100 % Residential MBS (4 ) 279 99 % (5 ) 139 97 % Commercial MBS (1 ) 147 99 % (1 ) 30 97 % Asset-backed securities (77 ) 5,406 99 % (23 ) 629 96 % Corporate and other (306 ) 10,378 97 % (128 ) 2,078 94 % Total fixed maturities $ (411 ) $ 17,766 98 % $ (192 ) $ 3,902 95 % December 31, 2017 Fixed maturities: U.S. Government and government agencies $ — $ 55 100 % $ (3 ) $ 123 98 % States, municipalities and political subdivisions (8 ) 825 99 % (10 ) 431 98 % Foreign government — 4 100 % — — — % Residential MBS (1 ) 118 99 % (5 ) 118 96 % Commercial MBS (1 ) 67 99 % — — — % Asset-backed securities (7 ) 1,195 99 % (9 ) 299 97 % Corporate and other (20 ) 2,031 99 % (18 ) 603 97 % Total fixed maturities $ (37 ) $ 4,295 99 % $ (45 ) $ 1,574 97 % Equity securities: Common stocks $ (22 ) $ 117 84 % $ — $ — — % Perpetual preferred stocks — 41 100 % (1 ) 13 93 % Total equity securities $ (22 ) $ 158 88 % $ (1 ) $ 13 93 % At December 31, 2018 , the gross unrealized losses on fixed maturities of $603 million relate to 2,324 securities. Investment grade securities (as determined by nationally recognized rating agencies) represented approximately 92% of the gross unrealized loss and 96% 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 interest 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. During 2018 , 2017 and 2016 , AFG recorded other-than-temporary impairment charges related to its residential MBS of $6 million , $1 million and $3 million , respectively. In 2018 , AFG recorded approximately $20 million in other-than-temporary impairment charges related to fixed maturities other than residential MBS, including $14 million related to aircraft financing. Other-than-temporary impairment charges on fixed maturities other than residential MBS were $19 million in 2017 and $35 million in 2016 . In addition, AFG recorded $4 million in other-than-temporary impairment charges in 2017 on investments that are included in other investments on the balance sheet. 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, 2018 . As discussed in Note A — “ Accounting Policies — Investments ,” effective January 1, 2018, all equity securities previously classified as “available for sale” are required to be carried at fair value through net earnings instead of accumulated other comprehensive income and therefore are no longer evaluated for other-than-temporary impairment. In 2017 and 2016 , AFG recorded other-than-temporary impairment charges on equity securities classified as available for sale of $64 million and $93 million , respectively. 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): 2018 2017 2016 Balance at January 1 $ 145 $ 153 $ 160 Additional credit impairments on: Previously impaired securities 1 1 2 Securities without prior impairments 1 3 1 Reductions due to sales or redemptions (5 ) (12 ) (10 ) Balance at December 31 $ 142 $ 145 $ 153 The table below sets forth the scheduled maturities of available for sale fixed maturities as of December 31, 2018 (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 $ 1,310 $ 1,318 3 % After one year through five years 8,521 8,554 20 % After five years through ten years 14,235 14,044 34 % After ten years 4,609 4,606 11 % 28,675 28,522 68 % ABS (average life of approximately 4.5 years) 9,781 9,811 23 % MBS (average life of approximately 4.5 years) 3,381 3,664 9 % Total $ 41,837 $ 41,997 100 % Certain risks are inherent in 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, 2018 or 2017 . Net Unrealized Gain on Marketable Securities In addition to adjusting fixed maturity securities and equity 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 Net December 31, 2018 Net unrealized gain on: Fixed maturities — annuity segment (a) $ 101 $ (21 ) $ 80 Fixed maturities — all other 59 (13 ) 46 Total fixed maturities 160 (34 ) 126 Deferred policy acquisition costs — annuity segment (42 ) 9 (33 ) Annuity benefits accumulated (14 ) 3 (11 ) Unearned revenue 1 — 1 Total net unrealized gain on marketable securities $ 105 $ (22 ) $ 83 December 31, 2017 Net unrealized gain on: Fixed maturities — annuity segment (a) $ 1,082 $ (227 ) $ 855 Fixed maturities — all other 259 (55 ) 204 Total fixed maturities 1,341 (282 ) 1,059 Equity securities (b) 279 (58 ) 221 Total investments 1,620 (340 ) 1,280 Deferred policy acquisition costs — annuity segment (433 ) 91 (342 ) Annuity benefits accumulated (137 ) 29 (108 ) Unearned revenue 13 (3 ) 10 Total net unrealized gain on marketable securities $ 1,063 $ (223 ) $ 840 (a) Net unrealized gains on fixed maturity investments supporting AFG’s annuity benefits accumulated. (b) As discussed in Note A — “ Accounting Policies — Investments ,” effective January 1, 2018, all equity securities other than those accounted for under the equity method are carried at fair value through net earnings. Net Investment Income The following table shows (in millions) investment income earned and investment expenses incurred. 2018 2017 2016 Investment income: Fixed maturities $ 1,742 $ 1,607 $ 1,510 Equity securities: Dividends 79 73 77 Change in fair value (*) 22 6 4 Equity in earnings of partnerships and similar investments 161 64 44 Other 112 102 81 Gross investment income 2,116 1,852 1,716 Investment expenses (22 ) (21 ) (20 ) Net investment income $ 2,094 $ 1,831 $ 1,696 (*) As discussed in Note A — “ Accounting Policies — Investments ,” AFG adopted guidance in January 2018 that requires all equity securities other than those accounted for under the equity method to be reported at fair value with holding gains and losses recognized in net earnings. Although the change in the fair value of the majority of AFG’s equity securities is recorded in realized gains (losses) on securities, AFG records holding gains and losses in net investment income on equity securities classified as “trading” under the previous guidance and on a small portfolio of limited partnership and similar investments that do not qualify for the equity method of accounting. Realized gains (losses) and changes in unrealized appreciation (depreciation) included in AOCI related to fixed maturity and equity security investments are summarized as follows (in millions): 2018 2017 Realized gains (losses) Realized gains (losses) Before Impairments Impairments Total Change in Unrealized Before Impairments Impairments Total Change in Unrealized Fixed maturities $ 6 $ (26 ) $ (20 ) $ (1,181 ) $ 17 $ (20 ) $ (3 ) $ 532 Equity securities (265 ) — (265 ) — 70 (64 ) 6 128 Mortgage loans and other investments 1 — 1 — (6 ) (4 ) (10 ) — Other (*) 11 7 18 502 (3 ) 15 12 (219 ) Total pretax (247 ) (19 ) (266 ) (679 ) 78 (73 ) 5 441 Tax effects: Reclassify impact of U.S. corporate tax rate change — — — — — — — 149 Other 52 4 56 143 (27 ) 25 (2 ) (154 ) Total tax effects 52 4 56 143 (27 ) 25 (2 ) (5 ) Net of tax $ (195 ) $ (15 ) $ (210 ) $ (536 ) $ 51 $ (48 ) $ 3 $ 436 2016 Realized gains (losses) Before Impairments Impairments Total Change in Unrealized Fixed maturities $ 36 $ (38 ) $ (2 ) $ 90 Equity securities 106 (93 ) 13 67 Other (*) (7 ) 15 8 (52 ) Total pretax 135 (116 ) 19 105 Tax effects (48 ) 41 (7 ) (37 ) Noncontrolling interests (2 ) 3 1 4 Net of tax and noncontrolling interests $ 85 $ (72 ) $ 13 $ 72 (*) Primarily adjustments to deferred policy acquisition costs and reserves related to the annuity business. As discussed in Note A — “ Accounting Policies — Investments ,” effective January 1, 2018, all equity securities other than those accounted for under the equity method are carried at fair value through net earnings. AFG recorded net holding gains (losses) on equity securities during 2018 on securities that were still owned at December 31, 2018 as follows (in millions): 2018 Included in realized gains (losses) $ (279 ) Included in net investment income 22 $ (257 ) Gross realized gains and losses (excluding impairment write-downs and mark-to-market of derivatives) on available for sale fixed maturity investment transactions consisted of the following (in millions): 2018 2017 2016 Fixed maturities: Gross gains $ 22 $ 43 $ 55 Gross losses (14 ) (20 ) (10 ) During 2017 and 2016 , AFG recorded gross gains of $87 million and $110 million and gross losses of $17 million and $4 million , respectively, on available for sale equity securities.

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives As discussed under “ Derivatives ” in Note A — “ Accounting Policies ,” 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): December 31, 2018 December 31, 2017 Derivative Balance Sheet Line Asset Liability Asset Liability MBS with embedded derivatives Fixed maturities $ 109 $ — $ 105 $ — Public company warrants Equity securities — — 4 — Fixed-indexed and variable-indexed annuities (embedded derivative) Annuity benefits accumulated — 2,720 — 2,542 Equity index call options Equity index call options 184 — 701 — Equity index put options Other liabilities — 1 — — Reinsurance contract (embedded derivative) Other liabilities — 2 — 4 $ 293 $ 2,723 $ 810 $ 2,546 The MBS with embedded derivatives consist of primarily interest-only and principal-only MBS. 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 are required to be carried at fair value through earnings. AFG’s fixed-indexed and variable-indexed annuities provide policyholders with a crediting rate tied, in part, to the performance of an existing stock market or other financial index. AFG attempts to mitigate the risk in the index-based component of these products through the purchase and sale of call and put options on the appropriate index. AFG receives collateral from certain counterparties to support its purchased call option assets (net of collateral required under put option contracts with the same counterparties). This collateral ( $103 million at December 31, 2018 and $389 million at December 31, 2017 ) 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 the change in the fair value of the call and put options will generally offset the economic change in the liabilities from the index participation. Both the index-based component of the annuities and the related call and put 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 , AFG has a reinsurance contract that is considered to contain an embedded derivative. The following table summarizes the gains (losses) included in AFG’s Statement of Earnings for changes in the fair value of derivatives that do not qualify for hedge accounting for 2018 , 2017 and 2016 (in millions): Derivative Statement of Earnings Line 2018 2017 2016 MBS with embedded derivatives Realized gains (losses) on securities $ (7 ) $ (6 ) $ (9 ) Public company warrants Realized gains (losses) on securities (3 ) — — Fixed-indexed and variable-indexed annuities (embedded derivative) (*) Annuity benefits 204 (589 ) (211 ) Equity index call options Annuity benefits (298 ) 494 141 Equity index put options Annuity benefits (1 ) — — Reinsurance contracts (embedded derivative) Net investment income 2 (2 ) (1 ) $ (103 ) $ (103 ) $ (80 ) (*) The change in fair value of the embedded derivative includes losses related to unlocking of actuarial assumptions of $44 million in 2018 , $25 million in 2017 and $17 million in 2016 . Derivatives Designated and Qualifying as Cash Flow Hedges As of December 31, 2018 , AFG has entered into sixteen interest rate swaps that are designated and qualify as highly effective cash flow hedges to mitigate interest rate risk related to certain floating-rate securities included in AFG’s portfolio of fixed maturity securities. The purpose of each of these swaps is to effectively convert a portion of AFG’s floating-rate fixed maturity securities to fixed rates by offsetting the variability in cash flows attributable to changes in short-term LIBOR. Under the terms of the swaps, AFG receives fixed-rate interest payments in exchange for variable interest payments based on short-term LIBOR. The notional amounts of the interest rate swaps generally decline over each swap’s respective life (the swaps expire between August 2019 and June 2030) in anticipation of the expected decline in AFG’s portfolio of fixed maturity securities with floating interest rates based on short-term LIBOR. The total outstanding notional amount of AFG’s interest rate swaps increased to $2.35 billion at December 31, 2018 compared to $1.58 billion at December 31, 2017 , reflecting six new swaps with an aggregate notional amount at issuance of $911 million entered into in 2018 , partially offset by the scheduled amortization discussed above. The fair value of the effective portion of the interest rate swaps in an asset position and included in other assets was $16 million at December 31, 2018 and less than $1 million at December 31, 2017 . The fair value of the effective portion of interest rate swaps in a liability position and included in other liabilities was $46 million at December 31, 2018 and $31 million at December 31, 2017 . The net unrealized gain or loss on cash flow hedges is included in AOCI, net of DPAC and deferred taxes. Amounts reclassified from AOCI (before DPAC and taxes) to net investment income were losses of $3 million in 2018 compared to income of $6 million in 2017 and $7 million in 2016 . There was no ineffectiveness recorded in net earnings during these periods. A collateral receivable supporting these swaps of $135 million at December 31, 2018 and $70 million at December 31, 2017 is included in other assets in AFG’s Balance Sheet.

Deferred Policy Acquisition Cos

Deferred Policy Acquisition Costs	12 Months Ended
	Dec. 31, 2018
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 Run-off Long-term Care and Life Deferred Deferred Sales Consolidated Costs Costs Inducements PVFP Subtotal Unrealized (*) Total Total Balance at December 31, 2015 $ 226 $ 1,018 $ 119 $ 55 $ 1,192 $ (234 ) $ 958 $ 1,184 Additions 535 230 9 — 239 — 239 774 Amortization: Periodic amortization (520 ) (169 ) (24 ) (9 ) (202 ) — (202 ) (722 ) Annuity unlocking — 25 4 — 29 — 29 29 Included in realized gains — 6 2 — 8 — 8 8 Foreign currency translation (3 ) — — — — — — (3 ) Change in unrealized — — — — — (31 ) (31 ) (31 ) Balance at December 31, 2016 238 1,110 110 46 1,266 (265 ) 1,001 1,239 Additions 588 225 4 — 229 — 229 817 Amortization: Periodic amortization (556 ) (161 ) (19 ) (8 ) (188 ) — (188 ) (744 ) Annuity unlocking — 34 6 1 41 — 41 41 Included in realized gains — 9 1 — 10 — 10 10 Foreign currency translation — — — — — — — — Other — — — 10 10 — 10 10 Change in unrealized — — — — — (157 ) (157 ) (157 ) Balance at December 31, 2017 270 1,217 102 49 1,368 (422 ) 946 1,216 Additions 675 263 2 — 265 — 265 940 Amortization: Periodic amortization (644 ) (238 ) (19 ) (7 ) (264 ) — (264 ) (908 ) Annuity unlocking — 29 — — 29 — 29 29 Included in realized gains — 14 1 — 15 — 15 15 Foreign currency translation (2 ) — — — — — — (2 ) Change in unrealized — — — — — 392 392 392 Balance at December 31, 2018 $ 299 $ 1,285 $ 86 $ 42 $ 1,413 $ (30 ) $ 1,383 $ 1,682 (*) Adjustments to DPAC related to net unrealized gains/losses on securities and cash flow hedges. The present value of future profits (“PVFP”) amounts in the table above are net of $148 million and $141 million of accumulated amortization at December 31, 2018 and 2017 , respectively. During each of the next five years, the PVFP is expected to decrease at a rate of approximately one-eighth of the balance at the beginning of each respective year.

Managed Investment Entities

Managed Investment Entities	12 Months Ended
	Dec. 31, 2018
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 60.9% of the most subordinate debt tranche of fifteen 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 2018, 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 $188 million (including $125 million invested in the most subordinate tranches) at December 31, 2018 , and $215 million at December 31, 2017 . In 2018 , AFG formed a new CLO, which issued $463 million face amount of liabilities (including $31 million face amount purchased by subsidiaries of AFG). During 2018 , AFG subsidiaries also purchased $7 million face amount of a senior debt tranche of an existing CLO for $7 million and received $45 million in sale and redemption proceeds from its CLO investments. In 2017 , AFG formed two new CLOs, which issued an aggregate of $865 million face amount of liabilities (including $48 million face amount purchased by subsidiaries of AFG). During 2017 , AFG subsidiaries also purchased $71 million face amount of senior debt and subordinate tranches of existing CLOs for $71 million and received $103 million in sale and redemption proceeds from its CLO investments. In 2016 , AFG formed two new CLOs, which issued an aggregate of $866 million face amount of liabilities (including $64 million face amount purchased by subsidiaries of AFG). During 2016, AFG subsidiaries also purchased $24 million face amount of senior debt and subordinate tranches of existing CLOs for $17 million and received $115 million in sale and redemption proceeds from its CLO investments. In 2018 and 2017 , one and two AFG CLOs, respectively, were substantially liquidated, as permitted by the CLO indentures. 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, 2018 2017 2016 Investment in CLO tranches $ 188 $ 215 $ 216 Gains (losses) on change in fair value of assets/liabilities (a): Assets (189 ) (8 ) 131 Liabilities 168 20 (116 ) Management fees paid to AFG 16 18 17 CLO earnings attributable to AFG Shareholders (b) 7 23 37 (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 $232 million and $55 million at December 31, 2018 and 2017 . The aggregate unpaid principal balance of the CLOs’ debt exceeded its carrying value by $241 million and $118 million at those dates. The CLO assets include loans with an aggregate fair value of $1 million at December 31, 2017 , for which the CLOs are not accruing interest because the loans are in default (aggregate unpaid principal balance of $8 million ; none at December 31, 2018 ).

Goodwill and Other Intangibles

Goodwill and Other Intangibles	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangibles	Goodwill and Other Intangibles Changes in the carrying value of goodwill during 2016 , 2017 and 2018 , by reporting segment, are presented in the following table (in millions): Property and Casualty Annuity Total Balance at January 1, 2016, December 31, 2016 and December 31, 2017 $ 168 $ 31 $ 199 Acquisition of subsidiary in 2018 8 — 8 Balance at December 31, 2018 $ 176 $ 31 $ 207 Goodwill increased by $8 million in the fourth quarter of 2018 due to the purchase of ABAIS as discussed in Note B — “ Acquisitions and Sale of Businesses .” Included in other assets in AFG’s Balance Sheet is $54 million at December 31, 2018 and $26 million at December 31, 2017 of amortizable intangible assets related to property and casualty insurance acquisitions. These amounts are net of accumulated amortization of $39 million and $30 million , respectively. The increase in amortizable intangible assets in 2018 relates to the November 2018 acquisition of ABAIS (discussed in Note B — “ Acquisitions and Sale of Businesses ” ) and a renewal rights intangible asset established in connection with the acquisition of a small property and casualty book of business in January 2018. Amortization of intangibles was $9 million in 2018 and $8 million in both 2017 and 2016 . Future amortization of intangibles (weighted average amortization period of 7 years ) is estimated to be $12 million per year in 2019 and 2020, $6 million in 2021, $4 million per year in 2022 and 2023 and $16 million thereafter.

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consisted of the following at December 31 (in millions): 2018 2017 Principal Discount and Issue Costs Carrying Value Principal Discount and Issue Costs Carrying Value Direct Senior Obligations of AFG: 4.50% Senior Notes due June 2047 $ 590 $ (2 ) $ 588 $ 590 $ (2 ) $ 588 3.50% Senior Notes due August 2026 425 (4 ) 421 425 (5 ) 420 Other 3 — 3 3 — 3 1,018 (6 ) 1,012 1,018 (7 ) 1,011 Direct Subordinated Obligations of AFG: 6-1/4% Subordinated Debentures due September 2054 150 (5 ) 145 150 (5 ) 145 6% Subordinated Debentures due November 2055 150 (5 ) 145 150 (5 ) 145 300 (10 ) 290 300 (10 ) 290 $ 1,318 $ (16 ) $ 1,302 $ 1,318 $ (17 ) $ 1,301 AFG has no scheduled principal payments on its long-term debt in the next five years. In June 2017, AFG issued $350 million in 4.50% Senior Notes due in 2047 at a price of 99.46% . The net proceeds of the offering were used to redeem AFG’s $230 million outstanding principal amount of 6-3/8% Senior Notes due June 2042 at par value and to redeem AFG’s $125 million outstanding principal amount of 5-3/4% Senior Notes due August 2042 at par value in June 2017 and August 2017, respectively. In November 2017, AFG issued an additional $125 million of 3.50% Senior Notes due in 2026 at a price of 99.698% and $240 million of 4.50% Senior Notes due in 2047 at a price of 102.374% . The net proceeds of the offering were used to redeem AFG’s $350 million outstanding principal amount of 9-7/8% Senior Notes due in June 2019 for $388 million (including a make-whole premium of $38 million ) in December 2017. In August 2016, AFG issued $300 million in 3.50% Senior Notes due in 2026 at a price of 99.608% . The net proceeds of the offering were used to fund a portion of the November 2016 acquisition of the noncontrolling interest in NATL (discussed in Note B — “ Acquisitions and Sale of Businesses ” ). At the acquisition date, the $18 million outstanding under NATL’s bank credit facility, including $6 million borrowed in September 2016, was repaid and the credit agreement was terminated. To achieve a desired balance between fixed and variable rate debt, AFG entered into an interest rate swap in June 2015, which effectively converted its 9-7/8% Senior Notes to a floating rate of three-month LIBOR plus 8.099% . In December 2017, AFG settled the interest rate swap contemporaneously with the redemption of the 9-7/8% Senior Notes. AFG can borrow up to $500 million under its revolving credit facility, which expires in June 2021. 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, 2018 or December 31, 2017 . Cash interest payments on long-term debt were $59 million in 2018 , $85 million in 2017 and $75 million in 2016 . In 2017 and 2016 , AFG received $2 million and $3 million , respectively, in interest under the interest rate swap discussed above.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2018
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, 2018 , there were 7.0 million shares of AFG Common Stock reserved for issuance under AFG’s stock incentive plans. 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, 2018 759,035 $ 73.40 Granted 200,625 $ 112.86 Vested (86,177 ) $ 56.89 Forfeited (7,553 ) $ 87.47 Outstanding at December 31, 2018 865,930 $ 84.06 The total fair value of restricted stock that vested during 2018 , 2017 and 2016 was $10 million , $14 million and $10 million , respectively. AFG issued 45,804 shares of Common Stock (fair value of $115.49 per share) in the first quarter of 2018 and 47,826 shares (fair value of $96.13 per share) in the first quarter of 2017 under its Equity Bonus Plan. AFG did not grant any stock options in 2018 , 2017 or 2016 . Options granted in years prior to 2016 have 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 Exercise Price Average Remaining Contractual Term Aggregate Intrinsic Value (in millions) Outstanding at January 1, 2018 3,467,340 $ 45.80 Exercised (778,270 ) $ 37.66 Forfeited/Cancelled (21,628 ) $ 42.10 Outstanding at December 31, 2018 2,667,442 $ 48.20 4.2 years $ 113 Options exercisable at December 31, 2018 2,253,003 $ 45.95 3.9 years $ 100 The total intrinsic value of options exercised during 2018 , 2017 and 2016 was $57 million , $65 million and $38 million , respectively. During 2018 , 2017 and 2016 , AFG received $29 million , $34 million and $32 million , respectively, in cash from the exercise of stock options. The total tax benefit related to the exercises was $9 million , $18 million and $11 million during those years, respectively. Total compensation expense related to stock incentive plans of AFG and its subsidiaries for 2018 , 2017 and 2016 was $23 million , $30 million and $28 million , respectively. AFG’s provision for income tax includes tax benefits of $13 million in 2018 , $27 million in 2017 and $19 million in 2016 related to AFG’s stock incentive plans. At December 31, 2018 , there was $3 million and $35 million of unrecognized compensation expense related to nonvested stock options and restricted stock awards, respectively. The nonvested stock options and restricted stock awards amounts are expected to be recognized over a weighted average of 1.0 year and 2.5 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 (Loss) AOCI Beginning Balance Pretax Tax Net of tax Attributable to noncontrolling interests Attributable to shareholders Other (c) AOCI Ending Balance Year ended December 31, 2018 Net unrealized gains (losses) on securities: Unrealized holding losses on securities arising during the period $ (689 ) $ 145 $ (544 ) $ — $ (544 ) Reclassification adjustment for realized (gains) losses included in net earnings (a) 10 (2 ) 8 — 8 Total net unrealized gains (losses) on securities (b) $ 840 (679 ) 143 (536 ) — (536 ) $ (221 ) $ 83 Net unrealized gains (losses) on cash flow hedges (13 ) 2 — 2 — 2 — (11 ) Foreign currency translation adjustments (6 ) (9 ) (1 ) (10 ) — (10 ) — (16 ) Pension and other postretirement plans adjustments (8 ) — — — — — — (8 ) Total $ 813 $ (686 ) $ 142 $ (544 ) $ — $ (544 ) $ (221 ) $ 48 Year ended December 31, 2017 Net unrealized gains on securities: Unrealized holding gains on securities arising during the period $ 456 $ (159 ) $ 297 $ — $ 297 Reclassification adjustment for realized (gains) losses included in net earnings (a) (15 ) 5 (10 ) — (10 ) Total net unrealized gains on securities (b) $ 404 441 (154 ) 287 — 287 $ 149 $ 840 Net unrealized losses on cash flow hedges (7 ) (6 ) 2 (4 ) — (4 ) (2 ) (13 ) Foreign currency translation adjustments (15 ) 9 3 12 — 12 (3 ) (6 ) Pension and other postretirement plans adjustments (7 ) 1 — 1 — 1 (2 ) (8 ) Total $ 375 $ 445 $ (149 ) $ 296 $ — $ 296 $ 142 $ 813 Year ended December 31, 2016 Net unrealized gains on securities: Unrealized holding gains on securities arising during the period $ 124 $ (44 ) $ 80 $ (4 ) $ 76 Reclassification adjustment for realized (gains) losses included in net earnings (a) (19 ) 7 (12 ) (1 ) (13 ) Total net unrealized gains on securities (b) $ 332 105 (37 ) 68 (5 ) 63 $ 9 $ 404 Net unrealized gains (losses) on cash flow hedges 1 (12 ) 4 (8 ) — (8 ) — (7 ) Foreign currency translation adjustments (22 ) 6 1 7 — 7 — (15 ) Pension and other postretirement plans adjustments (7 ) — — — — — — (7 ) Total $ 304 $ 99 $ (32 ) $ 67 $ (5 ) $ 62 $ 9 $ 375 (a) The reclassification adjustment out of net unrealized gains on securities affected the following lines in AFG’s Statement of Earnings: OCI component Affected line in the statement of earnings Pretax Realized gains (losses) on securities Tax Provision for income taxes Attributable to noncontrolling interests Net earnings attributable to noncontrolling interests (b) Includes net unrealized gains of $58 million at December 31, 2018 compared to net unrealized gains of $68 million and $52 million at December 31, 2017 and 2016 , related to securities for which only the credit portion of an other-than-temporary impairment has been recorded in earnings. (c) On January 1, 2018, AFG adopted new guidance that requires all equity securities other than those accounted for under the equity method to be reported at fair value with holding gains and losses recognized in net earnings. At the date of adoption, the $221 million net unrealized gain on equity securities classified as available for sale (with unrealized holding gains and losses reported in AOCI) under the prior guidance was reclassified from AOCI to retained earnings as the cumulative effect of an accounting change. Other also includes the December 2017 reclassification of $145 million stranded in AOCI from accounting for the Tax Cuts and Jobs Act of 2017 to retained earnings (see Note A — “ Accounting Policies — Income Taxes ”) , the impact on AOCI of the December 2017 sale of redeemable noncontrolling interests in Neon and the November 2016 acquisition of the noncontrolling interest in NATL (see Note B — “ Acquisitions and Sale of Businesses ”).

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The following is a reconciliation of income taxes at the statutory rate ( 21% in 2018 and 35% in both 2017 and 2016) to the provision for income taxes as shown in AFG’s Statement of Earnings (dollars in millions): 2018 2017 2016 Amount % of EBT Amount % of EBT Amount % of EBT Earnings before income taxes (“EBT”) $ 639 $ 724 $ 787 Income taxes at statutory rate $ 134 21 % $ 253 35 % $ 275 35 % Effect of: Tax exempt interest (13 ) (2 %) (23 ) (3 %) (24 ) (3 %) Adjustment to prior year taxes (8 ) (1 %) (4 ) (1 %) (2 ) — % Stock-based compensation (8 ) (1 %) (16 ) (2 %) (9 ) (1 %) Dividend received deduction (4 ) (1 %) (8 ) (1 %) (7 ) (1 %) Employee stock ownership plan dividend paid deduction (3 ) (1 %) (5 ) (1 %) (2 ) — % Foreign operations (2 ) — % 21 3 % 5 — % Change in valuation allowance (excluding change in tax rate) 11 2 % (7 ) (1 %) 52 7 % Nondeductible expenses 7 1 % 6 1 % 7 1 % Neon restructuring — — % (56 ) (8 %) (111 ) (14 %) Change in U.S corporate tax rate — — % 83 11 % — — % Acquisition of noncontrolling interest in NATL — — % — — % (66 ) (8 %) Subsidiaries not in AFG’s tax return — — % — — % 3 — % Other 8 1 % 3 1 % (2 ) (1 %) Provision for income taxes as shown in the statement of earnings $ 122 19 % $ 247 34 % $ 119 15 % The favorable impact of stock-based compensation on AFG’s effective tax rate in the year ended December 31, 2017 reflects the high volume of employee stock option exercises during that period and the increase in the market price of AFG Common Stock. In January 2008, AFG paid $75 million in cash to acquire approximately 67% of Neon Underwriting Limited (“Neon”, formerly known as Marketform Group Limited), a United Kingdom-based Lloyd’s insurer. During 2012, AFG acquired the then-remaining shares of Neon that it did not already own for $17 million . AFG’s investment in Neon includes the cost of acquiring the company as well as additional capital provided to Neon since the date of acquisition. In 2011, cumulative losses at Neon across multiple lines of business resulted in uncertainty concerning the realization of the deferred tax benefits associated with the losses. Consequently, AFG began maintaining a full valuation allowance against the deferred tax assets related to the Lloyd’s insurance business in 2011. Approximately $14 million of the $21 million impact of “foreign operations” for 2017 in the table above relates to a reduction in the “foreign underwriting losses” deferred tax asset as a result of the sale of the noncontrolling interest in Neon. Since AFG maintains a full valuation allowance against the deferred tax assets related to Neon, this reduction in deferred tax assets was offset by a corresponding reduction in the valuation allowance and had no overall impact on AFG’s income tax expense or results of operations. The changes in valuation allowance in the table above are primarily increases in the valuation allowance on tax benefits related to losses in the Neon Lloyd’s insurance business. The $61 million decrease in the valuation allowance in 2017 related to the change in the U.S. corporate tax rate is included in “Change in U.S. corporate tax rate” in table above. In connection with the reorganization of the Neon Lloyd’s business, in December 2016, AFG undertook a restructuring that included the liquidation for tax purposes of the foreign subsidiary that is the parent of the Neon Lloyd’s operations, resulting in a taxable loss for U.S. tax purposes. AFG reported a $111 million tax benefit associated with this loss in the fourth quarter of 2016. Approximately $29 million of the $111 million tax benefit recorded in 2016 reduced current taxes payable for 2016, while the remaining tax benefit was received in 2017 from the carry-back of the tax-basis capital loss to offset capital gains in prior years. An additional loss associated with the 2016 restructuring was deferred under U.S. tax laws, resulting in an unrecognized potential tax benefit of $48 million at December 31, 2016. The sale of the noncontrolling interest in Neon resulted in the recognition of an additional tax benefit of $56 million in the fourth quarter of 2017, including the recognition of the deferred loss from the 2016 restructuring. Approximately $20 million of the $56 million tax benefit recorded in 2017 reduced current taxes payable for 2017. The majority of the remaining 2017 tax benefit is expected to be received in 2019 as a result of the filing of a refund claim in 2018 to carry back tax basis capital losses to offset prior year tax basis capital gains. The Tax Cuts and Jobs Act of 2017 (“TCJA”), which was enacted on December 22, 2017, lowered the U.S corporate tax rate to 21% and made other widespread changes to the U.S. tax code effective in 2018. Because the TCJA was enacted in December 2017, AFG recorded the $83 million decrease in its net deferred tax asset resulting from the changes in the tax code (primarily the lower corporate tax rate applicable to 2018 and future years) in the fourth quarter of 2017. In addition to the lower U.S. corporate tax rate, the TCJA implemented a new global minimum tax on income earned by foreign subsidiaries of U.S.-based entities known as the Global Intangible Low-taxed Income (“GILTI”) provision. Since almost all of AFG’s earnings are taxable based on U.S. tax rates, the GILTI is not expected to be material to AFG’s results of operations and will be recorded in the period that any tax arises. At the time it was enacted, the TCJA was subject to further clarification and interpretation by the U.S. Treasury Department and the Internal Revenue Service. For example, the TCJA changed the way that companies calculate their insurance claims and reserves for tax purposes, including revaluing those tax basis liabilities as of January 1, 2018, based on a methodology and discount factors that had not been published. The resulting transitional deferred tax liability (taxes payable over eight years under the TCJA) and offsetting increase in AFG’s insurance claims and reserves deferred tax assets, were recorded at December 31, 2017 using reasonable estimates based on available information and were considered provisional in accordance with Securities and Exchange Commission Staff Accounting Bulletin No. 118 (“SAB 118”). Because the established transition liability was completely offset by an increase in related deferred tax assets, the adjustment to the final amount when the factors were published in 2018 did not impact AFG’s effective tax rate. In accordance with SAB 118, the insurance claims and reserves transitional deferred tax liability (and offsetting adjustment to the related deferred tax assets) and all other changes in deferred taxes resulting from clarification and interpretation of the TCJA were recorded in 2018 in the period in which the guidance was published and did not have a material impact on AFG’s effective tax rate. As a result, AFG’s implementation of the TCJA is complete as of December 31, 2018. As discussed in Note B — “ Acquisitions and Sale of Businesses ,” AFG acquired the noncontrolling interest in NATL in November 2016. This transaction allowed NATL and its subsidiaries to become members of the AFG consolidated tax group, which resulted in a tax benefit of $66 million to AFG during the fourth quarter of 2016. Excluding the tax benefit related to the Neon restructuring and the impact of the change in the U.S. corporate tax rate, AFG’s effective tax rate for the year ended December 31, 2017 was 31% . Excluding a $65 million charge related to the exit of certain lines of business within Neon and the tax benefits related to the acquisition of the noncontrolling interest in NATL and the Neon restructuring, AFG’s effective tax rate for the year ended December 31, 2016 was 35% . AFG’s 2012 — 2018 tax years remain subject to examination by the IRS. Total earnings before income taxes include losses subject to tax in foreign jurisdictions of $69 million in 2018 , $58 million in 2017 and $160 million in 2016 , primarily related to the Neon Lloyd’s operations. The total income tax provision (credit) consists of (in millions): 2018 2017 2016 Current taxes: Federal $ 196 $ 153 $ 299 State 8 6 12 Deferred taxes: Federal (82 ) 5 (192 ) Impact of change in U.S. corporate tax rate — 83 — Total Federal deferred taxes (82 ) 88 (192 ) Provision for income taxes $ 122 $ 247 $ 119 For income tax purposes, AFG and its subsidiaries had the following carryforwards available at December 31, 2018 (in millions): Expiring Amount Operating Loss – U.S. 2019 - 2022 $ 112 Operating Loss – United Kingdom indefinite 215 (*) (*) £168 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 AFG’s Balance Sheet at December 31 were as follows (in millions): 2018 2017 Excluding Unrealized Gains Impact of Unrealized Gains Total Excluding Unrealized Gains Impact of Unrealized Gains Total Deferred tax assets: Federal net operating loss carryforwards $ 23 $ — $ 23 $ 27 $ — $ 27 Foreign underwriting losses 93 — 93 80 — 80 Capital loss carryforwards — — — 32 — 32 Insurance claims and reserves 740 3 743 665 29 694 Employee benefits 88 — 88 84 — 84 Other, net 44 — 44 48 (3 ) 45 Total deferred tax assets before valuation allowance 988 3 991 936 26 962 Valuation allowance against deferred tax assets (119 ) — (119 ) (109 ) — (109 ) Total deferred tax assets 869 3 872 827 26 853 Deferred tax liabilities: Investment securities (36 ) (34 ) (70 ) (1 ) (340 ) (341 ) Deferred policy acquisition costs (300 ) 9 (291 ) (293 ) 91 (202 ) Insurance claims and reserves transition liability (110 ) — (110 ) (128 ) — (128 ) Real estate, property and equipment (36 ) — (36 ) (35 ) — (35 ) Total deferred tax liabilities (482 ) (25 ) (507 ) (457 ) (249 ) (706 ) Net deferred tax asset (liability) $ 387 $ (22 ) $ 365 $ 370 $ (223 ) $ 147 AFG’s net deferred tax asset at December 31, 2018 and 2017 is included in other assets in AFG’s Balance Sheet. The increase in AFG’s net deferred tax asset at December 31, 2018 compared to December 31, 2017 reflects significantly lower pretax unrealized gains on securities. 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 Neon Lloyd’s insurance business. Due to uncertainty concerning the realization of the deferred tax benefits associated with these losses, AFG maintains a full valuation allowance of $93 million against these deferred tax assets at December 31, 2018 . In addition to the valuation allowance related to the Neon Lloyd’s insurance business, the gross deferred tax asset has also been reduced by a $23 million valuation allowance related to 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. Approximately $19 million of AFG’s SRLY NOLs expired unutilized at December 31, 2018 . Since AFG maintains a full valuation allowance against its SRLY NOLs, the expiration of these loss carryforwards was offset by corresponding reduction in the valuation allowance and had no overall impact on AFG’s income tax expense or results of operations. AFG increased its liability for uncertain tax positions by $1 million in 2015 due to uncertainty in state taxation of its surplus lines insurance subsidiaries. In 2017, this uncertainty was resolved, resulting in total tax payments of less than $1 million . A progression of the liability for uncertain tax positions, excluding interest and penalties, follows (in millions): 2018 2017 2016 Balance at January 1 $ — $ 1 $ 1 Additions for tax positions of prior years — — — Reductions for tax positions of prior years — — — Additions for tax positions of current year — — — Settlements — (1 ) — Balance at December 31 $ — $ — $ 1 The total unrecognized tax benefits and related interest and penalties that, if recognized, would impact the effective tax rate is less than $1 million at December 31, 2018 and December 31, 2017 . AFG’s provision for income taxes in 2018 , 2017 and 2016 included interest expense related to unrecognized tax benefits of less than $1 million in each year (net of federal benefit or expense). There was no liability for interest related to unrecognized tax benefits at December 31, 2018 . AFG’s liability for interest related to unrecognized tax benefits was less than $1 million at December 31, 2017 (net of federal benefit). AFG’s provision for income taxes in 2018 , 2017 and 2016 included penalties of less than $1 million in each year. AFG’s liability for penalties related to unrecognized tax benefits was less than $1 million at December 31, 2018 and December 31, 2017 . Cash payments for income taxes, net of refunds, were $156 million , $194 million and $308 million for 2018 , 2017 and 2016 , respectively.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2018
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 2018. The review resulted in special A&E charges of $18 million for the property and casualty group and $9 million for the former railroad and manufacturing operations. AFG completed a comprehensive external study of its A&E exposures in the third quarter of 2017 with the aid of specialty actuarial, engineering and consulting firms and outside counsel. The study resulted in special A&E charges of $89 million for the property and casualty group and $24 million for the former railroad and manufacturing operations. AFG completed an in-depth internal review of its A&E exposures in the third quarter of 2016. The review resulted in special A&E charges of $36 million for the property and casualty group and $5 million for the former railroad and manufacturing operations. The property and casualty group’s liability for A&E reserves was $524 million at December 31, 2018 ; related recoverables from reinsurers (net of allowances for doubtful accounts) at that date were $129 million . At December 31, 2018 , American Premier and its subsidiaries had liabilities for environmental and personal injury claims and other contingencies aggregating $83 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, 2018 , GAFRI had a liability of $8 million for environmental costs and certain other matters associated with the sales of its former manufacturing operations. In December 2015, AFG completed the sale of substantially all of its run-off long-term care insurance business to HC2 Holdings, Inc. (“HC2”). In connection with obtaining regulatory approval for the transaction, AFG agreed to provide up to an aggregate of $35 million of capital support for the insurance companies, on an as-needed basis to maintain specified surplus levels, subject to immediate reimbursement by HC2 through a five-year capital maintenance agreement expiring in 2020. While management believes AFG has recorded adequate reserves for the items discussed above, 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, 2018
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, 2018 (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 Quarter 2nd Quarter 3rd Quarter 4th Quarter Total Year 2018 Revenues $ 1,619 $ 1,833 $ 2,008 $ 1,690 $ 7,150 Net earnings (losses), including noncontrolling interests 141 208 203 (35 ) 517 Net earnings (losses) attributable to shareholders 145 210 204 (29 ) 530 Earnings (losses) attributable to shareholders per Common Share: Basic $ 1.64 $ 2.36 $ 2.30 $ (0.33 ) $ 5.95 Diluted 1.60 2.31 2.26 (0.33 ) 5.85 Average number of Common Shares: Basic 88.6 89.0 89.1 89.3 89.0 Diluted 90.4 90.7 90.7 89.3 90.6 2017 Revenues $ 1,576 $ 1,646 $ 1,835 $ 1,808 $ 6,865 Net earnings, including noncontrolling interests 155 145 11 166 477 Net earnings attributable to shareholders 153 145 11 166 475 Earnings attributable to shareholders per Common Share: Basic $ 1.76 $ 1.64 $ 0.13 $ 1.88 $ 5.40 Diluted 1.72 1.61 0.13 1.84 5.28 Average number of Common Shares: Basic 87.2 87.8 88.1 88.2 87.8 Diluted 89.3 89.8 90.0 90.1 89.8 Pretax realized gains on subsidiaries and securities (including other-than-temporary impairments), favorable (adverse) prior year development of AFG’s liability for losses and loss adjustment expenses (“LAE”) and the impact of derivatives related to fixed-indexed and variable-indexed annuities (“FIAs”) were as follows (in millions): 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total Year Realized Gains (Losses) on Securities and Subsidiaries 2018 – change in fair value of equity securities $ (95 ) $ 23 $ 33 $ (223 ) $ (262 ) 2018 – other realized gains (losses) 2 8 1 (15 ) (4 ) 2017 3 8 (12 ) 6 5 Prior Year Development Favorable (Adverse) 2018 $ 56 $ 44 $ 31 $ 61 $ 192 2017 28 22 (52 ) 66 64 Impact of Derivatives related to FIAs Favorable (Adverse) 2018 $ 13 $ 3 $ (2 ) $ (47 ) $ (33 ) 2017 (2 ) (16 ) (4 ) (11 ) (33 ) As discussed in Note A — “ Accounting Policies — Investments ” and Note E — “ Investments ,” effective January 1, 2018, all equity securities other than those accounted for under the equity method are carried at fair value through net earnings. Realized gains (losses) on securities for the fourth quarter and full-year 2018 includes net holding losses on equity securities that were still owned at December 31, 2018 of $228 million and $279 million , respectively. Under the prior guidance, these holding losses would have been recorded in AOCI (with the exception of any impairment charge that may have been recorded). Prior year development in the third quarters of 2018 and 2017 includes pretax special charges of $18 million and $89 million , respectively, to strengthen property and casualty insurance A&E reserves. As a result of the Neon reinsurance to close agreement discussed in Note O — “ Insurance ,” Neon recorded $42 million in favorable development in the fourth quarter of 2017, of which $24 million related to its ongoing lines of business and $18 million related to its exited lines of business. FIAs provide policyholders with a crediting rate tied, in part, to the performance of an existing stock market or other financial index. AFG attempts to mitigate the risk in the index-based component of these products through the purchase and sale of call and put options on the appropriate index. AFG’s strategy is designed so that the change in the fair value of the call and put options will generally offset the economic change in the liabilities from the index participation. Both the index-based component of the annuities and the related call and put options are considered derivatives that must be marked-to-market through earnings each period. 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. In the table above, the impact of changes in the fair value of the derivatives related to FIAs is presented net of an estimate of the related acceleration/deceleration of the amortization of deferred policy acquisition costs and deferred sales inducements. The vast majority of AFG’s FIAs are indexed to the S&P 500, which decreased 14% in the fourth quarter of 2018. This poor stock market performance adversely impacted AFG’s earnings before income taxes from its annuity operations for the fourth quarter of 2018 beyond the impact on derivatives related to FIAs by $30 million , particularly related to FIAs with guaranteed withdrawal benefits. AFG recorded net charges as a result of updating (unlocking) actuarial assumptions underlying its annuity operations of $27 million in the second quarter of 2018, $4 million in the fourth quarter of 2018 and $3 million in the fourth quarter of 2017. AFG’s property and casualty operations recorded catastrophe losses totaling $103 million in 2018 (primarily from Hurricanes Florence and Michael and wildfires in California). Catastrophe losses for 2017 totaled $140 million , including $107 million in the third quarter (primarily from Hurricanes Harvey, Irma and Maria and earthquakes in Mexico). Results include pretax gains (included in other income) of $13 million from the sale of a hotel in the first quarter of 2017. Results for the third quarter of 2018 and 2017 include pretax special charges of $9 million and $24 million , respectively, to strengthen reserves for A&E exposures related to AFG’s former railroad and manufacturing operations. In 2017, AFG recorded pretax losses on the retirement of debt of $7 million in the second quarter, $4 million in the third quarter and $40 million in the fourth quarter. Net earnings in the fourth quarter of 2017 includes $56 million in tax benefits related to the Neon restructuring. See Note L — “ Income Taxes .”

Insurance

Insurance	12 Months Ended
	Dec. 31, 2018
Insurance [Abstract]
Insurance	Insurance Cash and securities owned by U.S.-based insurance subsidiaries, having a carrying value of approximately $1.06 billion at December 31, 2018 , were on deposit as required by regulatory authorities. In addition, $118 million was on deposit in support of AFG’s underwriting activities at Lloyd’s. At December 31, 2018 , AFG and its subsidiaries had $296 million in undrawn letters of credit ( none of which was collateralized) supporting the underwriting capacity of its U.K.-based Lloyd’s insurer, Neon. Property and Casualty Insurance Reserves Estimating the liability for unpaid losses and loss adjustment expenses (“LAE”) is inherently judgmental and is influenced by factors that are subject to significant variation. Determining the liability is a complex process incorporating input from many areas of the Company including actuarial, underwriting, pricing, claims and operations management. The process used to determine the total reserve for liabilities involves estimating the ultimate incurred losses and LAE, adjusted for amounts already paid on the claims. The IBNR reserve is derived by first estimating the ultimate unpaid reserve liability and subtracting case reserves for loss and LAE. In determining management’s best estimate of the ultimate liability, management (with the assistance of Company actuaries) considers items such as the effect of inflation on medical, hospitalization, material, repair and replacement costs, the nature and maturity of lines of insurance, general economic trends and the legal environment. In addition, historical trends adjusted for changes in underwriting standards, policy provisions, product mix and other factors are analyzed using actuarial reserve development techniques. Weighing all of the factors, the management team determines a single or “point” estimate that it records as its best estimate of the ultimate liability. Ranges of loss reserves are not developed by Company actuaries. This reserve analysis and review is completed each quarter and for almost every business within AFG’s property and casualty insurance sub-segments. Each review includes in-depth analysis of several hundred subdivisions of the business, employing multiple actuarial techniques. For each subdivision, actuaries use informed, professional judgment to adjust these techniques as necessary to respond to specific conditions in the data or within the business. Some of the standard actuarial methods employed for the quarterly reserve analysis may include (but may not be limited to): • Case Incurred Development Method • Paid Development Method • Bornhuetter-Ferguson Method • Incremental Paid LAE to Paid Loss Methods Management believes that each method has particular strengths and weaknesses and that no single estimation method is most accurate in all situations. When applied to a particular group of claims, the relative strengths and weaknesses of each method can change over time based on the facts and circumstances. Ultimately, the estimation methods chosen are those which management believes produce the most reliable indication for the particular liabilities under review. The period of time from the occurrence of a loss through the settlement of the liability is referred to as the “tail”. Generally, the same actuarial methods are considered for both short-tail and long-tail lines of business because most of them work properly for both. The methods are designed to incorporate the effects of the differing length of time to settle particular claims. For short-tail lines, management tends to give more weight to the Case Incurred and Paid Development methods, although the various methods tend to produce similar results. For long-tail lines, more judgment is involved, and more weight may be given to the Bornhuetter-Ferguson method. Liability claims for long-tail lines are more susceptible to litigation and can be significantly affected by changing contract interpretation and the legal environment. Therefore, the estimation of loss reserves for these classes is more complex and subject to a higher degree of variability. The level of detail in which data is analyzed varies among the different lines of business. Data is generally analyzed by major product or by coverage within product, using countrywide data; however, in some situations, data may be reviewed by state or region. Appropriate segmentation of the data is determined based on data credibility, homogeneity of development patterns, mix of business, and other actuarial considerations. Supplementary statistical information is also reviewed to determine which methods are most appropriate to use or if adjustments are needed to particular methods. Such information includes: • Open and closed claim counts • Average case reserves and average incurred on open claims • Closure rates and statistics related to closed and open claim percentages • Average closed claim severity • Ultimate claim severity • Reported loss ratios • Projected ultimate loss ratios • Loss payment patterns Within each business, results of individual methods are reviewed, supplementary statistical information is analyzed, and data from underwriting, operating and claim management are considered in deriving management’s best estimate of the ultimate liability. This estimate may be the result of one method, a weighted average of several methods, or a judgmental selection as the management team determines is appropriate. The liability for losses and LAE for a very limited number of claims with long-term scheduled payments under certain workers’ compensation policies has been discounted at 4.5% at both December 31, 2018 and 2017 , which represents an approximation of long-term investment yields. Because of the limited amount of claims involved, the net impact of discounting did not materially impact AFG’s total liability for unpaid losses and loss adjustment expenses (net reductions from discounting of $13 million and $15 million at December 31, 2018 and 2017 , respectively). The following table provides an analysis of changes in the liability for losses and loss adjustment expenses over the past three years (in millions): 2018 2017 2016 Balance at beginning of period $ 9,678 $ 8,563 $ 8,127 Less reinsurance recoverables, net of allowance 2,957 2,302 2,201 Net liability at beginning of period 6,721 6,261 5,926 Provision for losses and LAE occurring in the current year 3,195 3,019 2,730 Net increase (decrease) in the provision for claims of prior years: Special A&E charges 18 89 36 Neon exited lines charge — (18 ) 57 Other (210 ) (135 ) (61 ) Total losses and LAE incurred 3,003 2,955 2,762 Payments for losses and LAE of: Current year (963 ) (942 ) (841 ) Prior years (1,639 ) (1,586 ) (1,512 ) Total payments (2,602 ) (2,528 ) (2,353 ) Reserves of businesses disposed (*) (319 ) — (40 ) Foreign currency translation and other (4 ) 33 (34 ) Net liability at end of period 6,799 6,721 6,261 Add back reinsurance recoverables, net of allowance 2,942 2,957 2,302 Gross unpaid losses and LAE included in the balance sheet $ 9,741 $ 9,678 $ 8,563 (*) Reflects the reinsurance to close transactions at Neon (discussed below). The net decrease in the provision for claims of prior years in 2018 reflects (i) lower than expected losses in the crop business and lower than expected claim severity at National Interstate (within the Property and transportation sub-segment), (ii) lower than anticipated claim severity in the workers’ compensation businesses, lower than expected emergence in assumed 2017 property catastrophe losses at Neon and lower than expected claim severity in the executive liability business (within the Specialty casualty sub-segment) and (iii) lower than expected claim frequency and severity in the surety business, lower than expected claim severity in the fidelity business and lower than expected claim frequency in run-off businesses (within the Specialty financial sub-segment). This favorable development was partially offset by (i) the $18 million special charge to increase asbestos and environmental reserves and (ii) higher than expected claim frequency and severity in the Singapore branch and aviation operations (within the Property and transportation sub-segment). The net decrease in the provision for claims of prior years in 2017 reflects (i) lower than expected losses in the crop and equine businesses and lower than expected claim severity in the property and inland marine and transportation businesses (all within the Property and transportation sub-segment), (ii) favorable reserve development of $18 million on Neon’s exited lines, as well as additional favorable development on ongoing lines of business within Neon, recorded in connection with the reinsurance to close agreement entered into in December 2017 for the 2015 and prior years of account, lower than anticipated claim severity in the workers’ compensation businesses and lower than expected losses in the executive liability business (all within the Specialty casualty sub-segment) and (iii) lower than anticipated claim severity in the fidelity business and lower than expected claim frequency and severity in the surety business (both within the Specialty financial sub-segment). This favorable development was partially offset by (i) the $89 million special charge to increase asbestos and environmental reserves, (ii) higher than expected claim frequency and severity in the ocean marine business (within the Property and transportation sub-segment), (iii) higher than anticipated claim severity in the targeted markets and general liability businesses and higher than anticipated severity in New York contractor claims (all within the Specialty casualty sub-segment) and (iv) a charge to adjust to the deferred gain on the retroactive reinsurance transaction entered into in connection with the sale of businesses in 1998 (included in Other specialty sub-segment). The net increase in the provision for claims of prior years in 2016 reflects (i) the $36 million special charge to increase asbestos and environmental reserves, (ii) reserve strengthening at National Interstate and higher than expected claim frequency in the ocean marine business (within the Property and transportation sub-segment), (iii) adverse reserve development at Neon, higher than anticipated severity in New York contractor claims, higher than anticipated claim frequency and severity in general liability insurance and higher than expected claim frequency and severity in the targeted markets business (within the Specialty casualty sub-segment) and (iv) the $57 million special charge to increase loss reserves related to Neon’s exit of its UK and international medical malpractice and general liability lines of business. This adverse development was partially offset by (i) lower than expected losses in the crop business and lower than expected claim severity in the property and inland marine and trucking businesses (all within the Property and transportation sub-segment), (ii) lower than anticipated claim frequency and severity in workers’ compensation business, lower than expected claim severity in directors and officers liability insurance and lower than expected claim frequency and severity in excess liability business (all within the Specialty casualty sub-segment) and (iii) lower than anticipated claim severity in the fidelity and crime business, lower than expected claim frequency and severity in the surety business and lower than anticipated claim frequency in the financial institutions business (within the Specialty financial sub-segment). In December 2017, the Neon Lloyd’s syndicate entered into a reinsurance to close transaction for the 2015 and prior years of account with StarStone Underwriting Limited, a subsidiary of Enstar Group Limited, which was effective as of December 31, 2017 and settled in early 2018. In the Lloyd’s market, a reinsurance to close transaction transfers the responsibility for discharging all of the liabilities that attach to the transferred year of account plus the right to any income due to the closing year of account in return for a premium. This transaction provides Neon with finality on its legacy business. As a result of the reinsurance to close agreement, Neon was able to better estimate its ultimate liability for the 2015 and prior years of account as of December 31, 2017, resulting in favorable development of $42 million , of which $24 million related to its ongoing lines of business (included in Specialty casualty) and $18 million related to its exited lines of business (discussed below and included in Neon exited lines charge). In November 2016, the Neon Lloyd’s syndicate completed a similar reinsurance to close transaction with StarStone, which covered liabilities relating to the syndicate’s 2007 and prior years of account. That transaction also included a quota share of the Italian public hospital business written in Neon’s 2008 year of account and represented Neon’s complete exit from the Italian public hospital medical malpractice business. A reconciliation of incurred and paid claims development information to the aggregate carrying amount of the liability for unpaid losses and LAE, with separate disclosure of reinsurance recoverables on unpaid claims is shown below (in millions): 2018 Unpaid losses and allocated LAE, net of reinsurance: Specialty Property and transportation $ 1,117 Specialty casualty 3,884 Specialty financial 225 Other specialty 280 Total Specialty (excluding foreign reserves) 5,506 Other reserves Reserves for foreign operations: Neon Lloyd’s business 265 Other subsidiaries 268 A&E reserves 395 Unallocated LAE 335 Other 30 Total other reserves 1,293 Total reserves, net of reinsurance 6,799 Add back reinsurance recoverables, net of allowance 2,942 Gross unpaid losses and LAE included in the balance sheet $ 9,741 The following claims development tables and associated disclosures related to short-duration insurance contracts are prepared by sub-segment within the property and casualty insurance business for the most recent 10 accident years. AFG determines its claim counts at the claimant or policy feature level depending on the particular facts and circumstances of the underlying claim. While the methodology is generally consistent within each sub-segment, there are minor differences between and within the sub-segments. The methods used to summarize claim counts have not changed significantly over the time periods reported in the tables below. Property and transportation (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 503 $ 487 $ 505 $ 498 $ 494 $ 494 $ 491 $ 491 $ 491 $ 490 $ 2 138,248 2010 680 640 646 654 656 657 661 659 657 3 138,235 2011 816 803 819 833 844 856 853 850 6 139,345 2012 875 866 880 892 905 900 897 13 145,636 2013 894 881 884 890 890 890 18 141,293 2014 856 842 831 834 831 25 136,259 2015 831 794 789 789 36 134,484 2016 762 730 733 74 122,623 2017 904 868 128 140,963 2018 952 277 119,817 Total $ 7,957 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (a) 2009 $ 219 $ 333 $ 397 $ 440 $ 462 $ 476 $ 480 $ 481 $ 484 $ 485 99.0 % 2010 316 487 536 597 627 638 643 648 650 98.9 % 2011 367 670 732 777 810 828 836 839 98.7 % 2012 574 715 780 826 852 866 892 99.4 % 2013 440 710 769 814 843 859 96.5 % 2014 332 638 702 756 784 94.3 % 2015 361 587 675 717 90.9 % 2016 296 528 590 80.5 % 2017 383 648 74.7 % 2018 399 41.9 % Total $ 6,863 Unpaid losses and LAE — years 2009 through 2018 1,094 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) 23 Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 1,117 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 46.2 % 28.7 % 8.6 % 6.5 % 3.7 % 2.0 % 1.4 % 0.4 % 0.5 % 0.2 % Cumulative 46.2 % 74.9 % 83.5 % 90.0 % 93.7 % 95.7 % 97.1 % 97.5 % 98.0 % 98.2 % (a) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Specialty casualty (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 888 $ 887 $ 864 $ 844 $ 833 $ 828 $ 829 $ 824 $ 820 $ 811 $ 34 56,985 2010 870 886 887 865 879 868 867 864 853 47 56,411 2011 847 845 833 842 827 822 819 811 52 53,385 2012 890 883 876 876 872 867 838 64 51,885 2013 956 938 933 928 933 913 99 51,620 2014 1,023 994 994 992 966 139 54,494 2015 1,068 1,033 1,031 1,030 185 55,468 2016 1,115 1,108 1,097 313 53,038 2017 1,196 1,200 539 52,658 2018 1,257 705 48,996 Total $ 9,776 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (a) 2009 $ 170 $ 381 $ 510 $ 591 $ 653 $ 691 $ 715 $ 731 $ 740 $ 748 92.2 % 2010 191 411 559 644 699 735 756 770 782 91.7 % 2011 172 380 517 606 655 687 707 725 89.4 % 2012 171 378 508 611 674 713 735 87.7 % 2013 180 388 545 656 717 754 82.6 % 2014 187 406 565 668 741 76.7 % 2015 176 406 569 692 67.2 % 2016 184 411 571 52.1 % 2017 196 414 34.5 % 2018 207 16.5 % Total $ 6,369 Unpaid losses and LAE — years 2009 through 2018 3,407 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) 477 Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 3,884 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 19.1 % 23.2 % 16.2 % 11.1 % 7.0 % 4.3 % 2.6 % 1.9 % 1.3 % 1.0 % Cumulative 19.1 % 42.3 % 58.5 % 69.6 % 76.6 % 80.9 % 83.5 % 85.4 % 86.7 % 87.7 % (a) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Specialty financial (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 192 $ 192 $ 186 $ 184 $ 188 $ 186 $ 187 $ 186 $ 185 $ 186 $ 1 27,431 2010 138 145 132 132 135 133 130 127 126 1 21,922 2011 138 157 155 153 147 144 143 139 6 16,368 2012 163 163 151 139 137 135 132 6 21,064 2013 140 145 137 131 127 126 9 28,449 2014 146 157 156 153 147 9 29,411 2015 156 160 158 153 16 37,483 2016 179 184 187 24 44,820 2017 212 215 34 46,921 2018 212 79 36,606 Total $ 1,623 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (a) 2009 $ 112 $ 145 $ 157 $ 166 $ 171 $ 181 $ 185 $ 186 $ 186 $ 185 99.5 % 2010 61 93 104 122 132 130 128 126 126 100.0 % 2011 58 111 115 123 130 131 131 132 95.0 % 2012 71 104 109 117 121 126 128 97.0 % 2013 70 100 107 113 117 117 92.9 % 2014 62 109 125 128 137 93.2 % 2015 72 110 129 133 86.9 % 2016 88 141 158 84.5 % 2017 120 169 78.6 % 2018 112 52.8 % Total $ 1,397 Unpaid losses and LAE — years 2009 through 2018 226 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) (1 ) Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 225 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 50.5 % 26.4 % 7.5 % 5.8 % 4.7 % 1.7 % 0.5 % (0.1 %) — % (0.5 %) Cumulative 50.5 % 76.9 % 84.4 % 90.2 % 94.9 % 96.6 % 97.1 % 97.0 % 97.0 % 96.5 % (a) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Other specialty (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims (a) Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 41 $ 41 $ 41 $ 40 $ 37 $ 37 $ 36 $ 38 $ 33 $ 32 $ 6 — 2010 36 39 40 39 40 40 40 40 40 3 — 2011 39 43 42 43 43 44 44 43 3 — 2012 42 40 39 40 41 39 39 6 — 2013 46 47 46 47 50 53 2 — 2014 58 57 59 59 60 13 — 2015 59 60 63 66 8 — 2016 61 61 65 21 — 2017 63 65 36 — 2018 86 62 — Total $ 549 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (b) 2009 $ 8 $ 12 $ 15 $ 19 $ 22 $ 22 $ 24 $ 26 $ 25 $ 27 84.4 % 2010 8 14 21 24 27 33 35 36 37 92.5 % 2011 12 20 25 28 34 36 37 38 88.4 % 2012 8 17 21 25 28 30 30 76.9 % 2013 7 16 22 34 37 44 83.0 % 2014 13 21 30 36 43 71.7 % 2015 10 26 31 50 75.8 % 2016 9 19 31 47.7 % 2017 10 19 29.2 % 2018 12 14.0 % Total $ 331 Unpaid losses and LAE — years 2009 through 2018 218 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) 62 Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 280 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 18.7 % 17.0 % 12.6 % 14.1 % 9.3 % 7.6 % 3.4 % 3.7 % (0.3 %) 6.3 % Cumulative 18.7 % 35.7 % 48.3 % 62.4 % 71.7 % 79.3 % 82.7 % 86.4 % 86.1 % 92.4 % (a) The amounts shown in Other specialty represent business assumed by AFG’s internal reinsurance program from the operations that make up AFG’s other Specialty property and casualty insurance sub-segments. Accordingly, the liability for incurred claims and allocated LAE represents additional reserves held on claims counted in the tables provided for the other sub-segments (above). (b) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Total Specialty Group (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 1,624 $ 1,607 $ 1,596 $ 1,566 $ 1,552 $ 1,545 $ 1,543 $ 1,539 $ 1,529 $ 1,519 $ 43 222,664 2010 1,724 1,710 1,705 1,690 1,710 1,698 1,698 1,690 1,676 54 216,568 2011 1,840 1,848 1,849 1,871 1,861 1,866 1,859 1,843 67 209,098 2012 1,970 1,952 1,946 1,947 1,955 1,941 1,906 89 218,585 2013 2,036 2,011 2,000 1,996 2,000 1,982 128 221,362 2014 2,083 2,050 2,040 2,038 2,004 186 220,164 2015 2,114 2,047 2,041 2,038 245 227,435 2016 2,117 2,083 2,082 432 220,481 2017 2,375 2,348 737 240,542 2018 2,507 1,123 205,419 Total $ 19,905 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (a) 2009 $ 509 $ 871 $ 1,079 $ 1,216 $ 1,308 $ 1,370 $ 1,404 $ 1,424 $ 1,435 $ 1,445 95.1 % 2010 576 1,005 1,220 1,387 1,485 1,536 1,562 1,580 1,595 95.2 % 2011 609 1,181 1,389 1,534 1,629 1,682 1,711 1,734 94.1 % 2012 824 1,214 1,418 1,579 1,675 1,735 1,785 93.7 % 2013 697 1,214 1,443 1,617 1,714 1,774 89.5 % 2014 594 1,174 1,422 1,588 1,705 85.1 % 2015 619 1,129 1,404 1,592 78.1 % 2016 577 1,099 1,350 64.8 % 2017 709 1,250 53.2 % 2018 730 29.1 % Total $ 14,960 Unpaid losses and LAE — years 2009 through 2018 4,945 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) 561 Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 5,506 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 32.6 % 25.5 % 12.2 % 8.8 % 5.5 % 3.2 % 2.0 % 1.2 % 0.8 % 0.7 % Cumulative 32.6 % 58.1 % 70.3 % 79.1 % 84.6 % 87.8 % 89.8 % 91.0 % 91.8 % 92.5 % (a) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Closed Block of Long-Term Care Insurance Following the completion of the sale of substantially all of its run-off long-term care insurance business in December 2015, AFG’s remaining long-term care insurance reserves were $45 million at December 31, 2018 and $39 million at December 31, 2017 , net of reinsurance recoverables and excluding the impact of unrealized gains on securities. AFG’s remaining 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. 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 $47 million investment in FHLB capital stock at December 31, 2018 is included in other investments at cost. Membership in the FHLB provides the annuity operations with an 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 fourth quarter of 2018, GALIC refinanced the terms on a $40 million advance to extend the maturity and the FHLB advanced GALIC $225 million , increasing the total amount advanced to $1.10 billion (included in annuity benefits accumulated) at December 31, 2018. In 2017, GALIC refinanced the terms on advances totaling $831 million , which lowered the weighted average spread over LIBOR. Interest rates under the various funding agreements on the advances range from 0.15% to 0.24% over LIBOR (average rate of 2.68% at December 31, 2018 ). While these advances must be repaid between 2019 and 2021 ( $445 million in 2019, $40 million in 2020 and $611 million in 2021), GALIC has the option to prepay all or a portion of the advances. GALIC has invested the proceeds from the advances in fixed maturity securities with similar expected lives as the advances for the purpose of earning a spread over the interest payments due to the FHLB. The advances on these agreements are collateralized by fixed maturity investments, which have a total fair value of $1.28 billion (included in available for sale fixed maturity securities) at December 31, 2018 . Interest credited on the funding agreements, which is included in annuity benefits, was $20 million in 2018 , $14 million in 2017 and $8 million in 2016 . 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 2018 2017 2016 2018 2017 Property and casualty companies $ 546 $ 484 $ 461 $ 2,867 $ 2,729 Life insurance companies 802 286 167 2,701 2,132 In the fourth quarter of 2018, GALIC, AFG’s primary annuity subsidiary, entered into a reinsurance treaty with Hannover Life Reassurance Company of America that transfers the risk of certain surrender activity in GALIC’s fixed-indexed annuity business. This treaty meets the statutory risk transfer rules and resulted in a $510 million increase in statutory surplus (through an after-tax reserve credit), which is reflected in the life insurance companies capital and surplus in the table above. Under GAAP, this transaction does not meet the GAAP insurance risk transfer criteria and did not have a material impact on AFG’s financial statements. 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, 2018 and 2017 , 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, 2018 or 2017 . 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 2019 from its insurance subsidiaries without seeking regulatory approval is $1.30 billion . Additional amounts of dividends require regulatory approval. Holding Company Dividends AFG declared and paid common stock dividends to shareholders totaling $397 million , $421 million and $187 million in 2018 , 2017 and 2016 , respectively. Currently, there are no regulatory restrictions on AFG’s retained earnings or net earnings that materially impact its ability to pay dividends. Based on shareholders’ equity at December 31, 2018 , AFG could pay dividends of nearly $2 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. However, AFG remains liable to its insureds regardless of whether a reinsurer is able to meet its obligations. 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. 2018 2017 2016 Direct premiums written $ 6,626 $ 6,310 $ 5,858 Reinsurance assumed 214 192 123 Reinsurance ceded (1,817 ) (1,751 ) (1,595 ) Net written premiums $ 5,023 $ 4,751 $ 4,386 Direct premiums earned $ 6,472 $ 6,112 $ 5,745 Reinsurance assumed 204 157 118 Reinsurance ceded (1,811 ) (1,690 ) (1,535 ) Net earned premiums $ 4,865 $ 4,579 $ 4,328 Reinsurance recoveries $ 1,249 $ 1,379 $ 810 In June 2017, AFG’s property and casualty insurance subsidiaries entered into a reinsurance agreement to obtain supplemental catastrophe protection through a catastrophe bond structure with Riverfront Re Ltd. (“Riverfront”). The reinsurance agreement provides supplemental reinsurance coverage up to 95% of $200 million (fully collateralized) for catastrophe losses in excess of $104 million (per occurrence and annual aggregate) occurring between June 1, 2017 and December 31, 2020. In connection with the reinsurance agreement, Riverfront issued notes to unrelated investors for the full amount of coverage provided under the reinsurance agreement. Through December 31, 2018 , AFG’s incurred catastrophe losses have not reached the level of attachment for the catastrophe bond structure. Riverfront is a variable interest entity in which AFG does not have a variable interest because the variability in Riverfront’s results will 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 reinsuranc

Additional Information

Additional Information	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Additional Information	Additional Information Allowance for Uncollectible Reinsurance AFG’s aggregate allowance for uncollectible reinsurance recoverables was $18 million at December 31, 2018 and $20 million at December 31, 2017 . AFG reviews the allowance quarterly and adjusts it as necessary to reflect changes in estimates of uncollectible balances. AFG recorded net expense reductions against the allowance of $2 million in 2018 and less than $1 million in both 2017 and 2016. In 2017, the allowance was reduced by reinsurance recoverable write-offs of $2 million . Operating Leases Total rental expense for various leases of office space and equipment was $70 million in 2018 , $69 million in 2017 and $67 million in 2016 . 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, 2018 , were as follows: 2019 – $65 million ; 2020 – $57 million ; 2021 – $50 million ; 2022 – $40 million ; 2023 – $35 million ; and $79 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, 2018 , AFG and its subsidiaries had commitments to fund credit facilities and contribute capital to limited partnerships and limited liability corporations of approximately $949 million . Benefit Plans AFG expensed approximately $37 million in 2018 , $45 million in 2017 and $43 million in 2016 for its retirement and employee savings plans.

Condensed Financial Information

Condensed Financial Information of Parent Company	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information 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, 2018 2017 Assets: Cash and cash equivalents $ 158 $ 299 Investment in securities 65 70 Investment in subsidiaries (a) 6,155 6,310 Other investments 2 2 Other assets 68 141 Total assets $ 6,448 $ 6,822 Liabilities and Equity: Long-term debt $ 1,302 $ 1,301 Other liabilities 176 191 Shareholders’ equity 4,970 5,330 Total liabilities and equity $ 6,448 $ 6,822 Condensed Statement of Earnings Year ended December 31, 2018 2017 2016 Revenues: Dividends from subsidiaries $ 261 $ 681 $ 643 Equity in undistributed earnings of subsidiaries 529 264 286 Investment and other income 2 13 7 Total revenues 792 958 936 Costs and Expenses: Interest charges on intercompany borrowings 8 9 9 Interest charges on other borrowings 62 85 77 Other expenses 70 142 82 Total costs and expenses 140 236 168 Earnings before income taxes 652 722 768 Provision for income taxes 122 247 119 Net Earnings Attributable to Shareholders $ 530 $ 475 $ 649 Condensed Statement of Comprehensive Income Net earnings attributable to shareholders $ 530 $ 475 $ 649 Other comprehensive income (loss), net of tax (544 ) 296 62 Total comprehensive income (loss), net of tax $ (14 ) $ 771 $ 711 ________________________ (a) Investment in subsidiaries includes intercompany receivables and payables. Condensed Statement of Cash Flows Year ended December 31, 2018 2017 2016 Operating Activities: Net earnings attributable to shareholders $ 530 $ 475 $ 649 Adjustments: Equity in net earnings of subsidiaries (637 ) (575 ) (638 ) Dividends from subsidiaries 238 580 611 Other operating activities, net 84 98 (67 ) Net cash provided by operating activities 215 578 555 Investing Activities: Capital contributions to subsidiaries (11 ) (93 ) (560 ) Returns of capital from subsidiaries 23 30 — Purchases of investments, property and equipment (5 ) (2 ) (1 ) Proceeds from maturities and redemptions of investments 3 2 1 Net cash provided by (used in) investing activities 10 (63 ) (560 ) Financing Activities: Additional long-term borrowings — 712 296 Reductions of long-term debt — (745 ) — Issuances of Common Stock 34 37 35 Repurchases of Common Stock (6 ) — (133 ) Cash dividends paid on Common Stock (394 ) (417 ) (185 ) Net cash provided by (used in) financing activities (366 ) (413 ) 13 Net Change in Cash and Cash Equivalents (141 ) 102 8 Cash and cash equivalents at beginning of year 299 197 189 Cash and cash equivalents at end of year $ 158 $ 299 $ 197

Supplementary Insurance Informa

Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
Supplementary Insurance Information	AMERICAN FINANCIAL GROUP, INC. AND SUBSIDIARIES SCHEDULE III — SUPPLEMENTARY INSURANCE INFORMATION THREE YEARS ENDED DECEMBER 31, 2018 (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) 2018 Property and casualty insurance $ 299 $ 9,741 $ 2,595 $ 4,865 $ 438 $ 3,003 $ 644 $ 957 $ 5,023 Annuity 1,360 36,616 — — 1,638 998 212 174 — Other 23 635 — 24 18 40 4 479 3 Total $ 1,682 $ 46,992 $ 2,595 $ 4,889 $ 2,094 $ 4,041 $ 860 $ 1,610 $ 5,026 2017 Property and casualty insurance $ 270 $ 9,678 $ 2,410 $ 4,579 $ 362 $ 2,955 $ 556 $ 867 $ 4,751 Annuity 920 33,316 — — 1,458 892 130 159 — Other 26 658 — 22 11 26 4 552 3 Total $ 1,216 $ 43,652 $ 2,410 $ 4,601 $ 1,831 $ 3,873 $ 690 $ 1,578 $ 4,754 2016 Property and casualty insurance $ 238 $ 8,563 $ 2,171 $ 4,328 $ 350 $ 2,762 $ 520 $ 870 $ 4,386 Annuity 981 29,907 — — 1,356 800 149 142 — Other 20 691 — 24 (10 ) 33 4 431 3 Total $ 1,239 $ 39,161 $ 2,171 $ 4,352 $ 1,696 $ 3,595 $ 673 $ 1,443 $ 4,389

Accounting Policies (Policies)

Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of American Financial Group, Inc. and its subsidiaries (“AFG”). 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, 2018 , 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. AFG did not have any significant nonrecurring fair value measurements of nonfinancial assets and liabilities in 2018 or 2017 .
Investments	Investments On January 1, 2018, AFG adopted Accounting Standards Update (“ASU”) 2016-01, which requires all equity securities other than those accounted for under the equity method to be reported at fair value with holding gains and losses recognized in net earnings. At December 31, 2017, AFG had $1.60 billion in equity securities classified as “available for sale” under the prior guidance with holding gains and losses included in accumulated other comprehensive income (“AOCI”) instead of net earnings. At the date of adoption, the $221 million net unrealized gain on equity securities included in AOCI was reclassified to retained earnings as the cumulative effect of an accounting change. The cumulative effect of the accounting change also includes the net unrealized gain on AFG’s small number of limited partnerships and similar investments carried at cost under the prior guidance that are carried at fair value through net earnings under the new guidance ( $4 million net of tax at the date of adoption). Holding gains and losses on equity securities carried at fair value under ASU 2016-01 are generally recorded in realized gains (losses) on securities. However, prior to the adoption of the new guidance, AFG classified a small portion of its equity securities as “trading” and reported those investments at fair value with holding gains and losses recognized in net investment income. These investments consisted primarily of equity securities held to offset the impact of changes in the stock market on employee benefit plans that are impacted by stock market performance and totaled $62 million at December 31, 2017. Following the adoption of the new guidance, AFG continues to record holding gains and losses on these securities, as well as its small portfolio of limited partnerships and similar investments carried at fair value under the new guidance and certain other securities classified at purchase as “fair value through net investment income” in net investment income. Under the new guidance, AFG recorded holding losses of $257 million on equity securities in net earnings during 2018 on securities that were still owned at December 31, 2018 . Under the prior guidance, these holding losses would have been recorded in AOCI (with the exception of any impairment charge that may have been recorded). Because almost all of the equity securities impacted by the new guidance were carried at fair value through AOCI under the prior guidance, the adoption of the new guidance did not have a material impact on AFG’s financial position. Fixed maturity securities classified as “available for sale” are reported at fair value with unrealized gains and losses included in AOCI in AFG’s Balance Sheet. Fixed maturity 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 effective 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. Limited partnerships and similar investments are generally accounted for using the equity method of accounting. Under the equity method, AFG records its share of the earnings or losses of the investee based on when they are reported by the investee in its financial statements rather than in the period in which the investee declares a dividend. AFG’s share of the earnings or losses from equity method investments is generally recorded on a quarter lag due to the timing of the receipt of the investee’s financial statements. AFG’s equity in the earnings (losses) of limited partnerships and similar investments is included in net investment income. Gains or losses on fixed-maturity 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 and qualify as highly effective 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 and principal-only MBS) and (ii) the equity-based component of certain annuity products (included in annuity benefits accumulated) and related equity index options 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 impacts 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 statement of earnings as the cash flows from the hedged item. AFG uses interest rate swaps that are designated and qualify as highly effective cash flow hedges to mitigate interest rate risk related to certain floating-rate securities included in AFG’s portfolio of fixed maturity securities. For derivatives that are designated and qualify as highly effective fair value hedges, changes in the fair value of the derivative, along with changes in the fair value of the hedged item attributable to the hedged risk, are recognized in current period earnings.
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. An AFG 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 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 ” ). 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) through its investment in the CLO debt tranches, it has exposure to CLO losses (limited to the amount AFG invested) and the right to receive CLO benefits that 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. 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 net gain or loss from accounting for the CLO assets and liabilities at fair value is presented separately in AFG’s Statement of Earnings. The fair values of a CLO’s assets may differ from the separately measured fair values of its liabilities even though the CLO liabilities only have recourse to the CLO assets. AFG has 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 a separately measured fair value. CLO earnings attributable to AFG’s shareholders are measured by the change in the fair value of AFG’s investments in the CLOs and management fees earned.
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 annuity benefits expense and decreases for annuity policy charges are recorded in other income. For traditional fixed annuities, the liability for annuity benefits accumulated represents the account value that had accrued to the benefit of the policyholder as of the balance sheet date. For fixed-indexed annuities, the liability for annuity benefits accumulated includes an embedded derivative that represents the estimated fair value of the index participation with the remaining component representing the discounted value of the guaranteed minimum contract benefits. 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 (included in other income) 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 (losses) 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.
Debt Issuance Costs	Debt Issuance Costs Debt issuance costs related to AFG’s outstanding debt are presented in its Balance Sheet as a direct reduction in the carrying value of long-term debt and are amortized over the life of the related debt using the effective interest method as a component of interest expense. Debt issuance costs related to AFG’s revolving credit facilities are included in other assets 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 represent 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. Noncontrolling interests that are redeemable at the option of the holder are presented separately in the mezzanine section of the balance sheet (between liabilities and equity).
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. The effect of a change in tax rates on deferred tax assets and liabilities is recorded in net earnings in the period that includes the enactment date. This includes the impact on deferred tax assets or liabilities established through AOCI, which results in an amount equal to the difference between the deferred tax at the historical corporate rate and the newly enacted rate stranded in AOCI. As permitted under guidance adopted effective December 31, 2017 (ASU 2018-02), AFG reclassified the $145 million stranded in AOCI from accounting for the Tax Cuts and Jobs Act of 2017 to retained earnings at December 31, 2017. See Note L — “ Income Taxes ” for further information.
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: 2018 – 1.6 million , 2017 – 2.0 million and 2016 – 1.6 million . AFG’s weighted average diluted shares outstanding excludes the following anti-dilutive potential common shares related to stock compensation plans: 2018 and 2017 – none and 2016 – 0.4 million . Adjustments to net earnings attributable to shareholders in the calculation of diluted earnings per share were nominal in the 2018 , 2017 and 2016 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, property and equipment and businesses. “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.
New Accounting Pronouncements	Revenue Recognition Guidance Effective in 2018 On January 1, 2018, AFG adopted ASU 2014-09, which provides guidance on recognizing revenue when (or as) performance obligations under the contract are satisfied. The new guidance also updates the accounting for certain costs associated with obtaining and fulfilling contracts with customers and requires certain new disclosures. Because revenue recognition for insurance contracts and financial instruments (AFG’s primary sources of revenue) were excluded from the scope of the new guidance, the adoption of ASU 2014-09 did not have a material impact on AFG’s results of operations and financial position. Lease Accounting Guidance Effective in 2019 In February 2016, the FASB issued ASU 2016-02, which requires entities that lease assets for terms longer than one year to recognize the assets and liabilities for the rights and obligations created by those leases on the balance sheet based on the present value of contractual cash flows. Qualitative and quantitative disclosures of the amount, timing and uncertainty of cash flows arising from leases will also be required. AFG will adopt the updated guidance effective January 1, 2019. The new guidance will not have a material effect on AFG’s results of operations because it does not change the manner in which lease-related expenses are recognized in the statement of earnings. In addition, the new guidance will not have a material effect on AFG’s financial position as recognizing the assets and liabilities related to operating leases upon adoption of the new guidance in January 2019 will increase AFG’s consolidated assets and consolidated liabilities by less than one-half of 1% as compared to AFG’s Balance Sheet at December 31, 2018.

Acquisitions and Sale of Busi_2

Acquisitions and Sale of Businesses (Tables)	12 Months Ended
	Dec. 31, 2018
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): November 30, Total purchase price $ 30 Tangible assets acquired 28 Liabilities acquired 26 Net tangible assets acquired, at fair value 2 Excess purchase price over net tangible assets acquired $ 28 Allocation of excess purchase price: Intangible assets acquired (*) $ 25 Deferred tax on intangible assets acquired (*) (5 ) Goodwill 8 $ 28 (*) Included in Other assets in AFG’s Balance Sheet.

Segments of Operations (Tables)

Segments of Operations (Tables)	12 Months Ended
	Dec. 31, 2018
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. 2018 2017 2016 Assets Property and casualty insurance (a) $ 17,681 $ 17,171 $ 15,574 Annuity 39,952 37,179 33,409 Other 5,823 6,308 6,089 Total assets $ 63,456 $ 60,658 $ 55,072 Revenues Property and casualty insurance: Premiums earned: Specialty Property and transportation $ 1,729 $ 1,711 $ 1,662 Specialty casualty 2,403 2,186 2,006 Specialty financial 598 576 557 Other specialty 135 106 103 Total premiums earned 4,865 4,579 4,328 Net investment income 438 362 350 Other income (b) 10 28 51 Total property and casualty insurance 5,313 4,969 4,729 Annuity: Net investment income 1,638 1,458 1,356 Other income 107 103 103 Total annuity 1,745 1,561 1,459 Other 358 330 289 Total revenues before realized gains (losses) 7,416 6,860 6,477 Realized gains (losses) on securities (266 ) 5 19 Realized gains on subsidiaries — — 2 Total revenues $ 7,150 $ 6,865 $ 6,498 (a) Not allocable to sub-segments. (b) Includes income of $32 million (before noncontrolling interest) from the sale of an apartment property in 2016. 2018 2017 2016 Earnings Before Income Taxes Property and casualty insurance: Underwriting: Specialty Property and transportation $ 120 $ 154 $ 166 Specialty casualty 141 104 78 Specialty financial 66 61 84 Other specialty (5 ) (2 ) 9 Other lines (a) (20 ) (75 ) (101 ) Total underwriting 302 242 236 Investment and other income, net (b) 407 349 341 Total property and casualty insurance 709 591 577 Annuity 361 380 368 Other (c) (165 ) (252 ) (179 ) Total earnings before realized gains (losses) and income taxes 905 719 766 Realized gains (losses) on securities (266 ) 5 19 Realized gains on subsidiaries — — 2 Total earnings before income taxes $ 639 $ 724 $ 787 (a) Includes special charges to increase asbestos and environmental (“A&E”) reserves of $18 million , $89 million and $36 million in 2018 , 2017 and 2016 , respectively. Also includes $18 million in favorable development related to the Neon exited lines recorded in connection with a reinsurance to close transaction in 2017 and a charge of $65 million related to Neon exited lines in 2016. (b) Includes income of $32 million (before noncontrolling interest) from the sale of an apartment property in 2016. (c) Primarily holding company interest and expenses, including losses on retirement of debt of $51 million in 2017 and special charges to increase A&E reserves related to AFG’s former railroad and manufacturing operations ( $9 million in 2018 , $24 million in 2017 and $5 million in 2016 ).

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2018
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 December 31, 2018 Assets: Available for sale (“AFS”) fixed maturities: U.S. Government and government agencies $ 141 $ 83 $ 9 $ 233 States, municipalities and political subdivisions — 6,880 59 6,939 Foreign government — 142 — 142 Residential MBS — 2,547 197 2,744 Commercial MBS — 864 56 920 Asset-backed securities — 8,964 847 9,811 Corporate and other 28 19,184 1,996 21,208 Total AFS fixed maturities 169 38,664 3,164 41,997 Trading fixed maturities 9 96 — 105 Equity securities 1,410 68 336 1,814 Equity index call options — 184 — 184 Assets of managed investment entities (“MIE”) 203 4,476 21 4,700 Variable annuity assets (separate accounts) (*) — 557 — 557 Other assets — derivatives — 16 — 16 Total assets accounted for at fair value $ 1,791 $ 44,061 $ 3,521 $ 49,373 Liabilities: Liabilities of managed investment entities $ 195 $ 4,297 $ 20 $ 4,512 Derivatives in annuity benefits accumulated — — 2,720 2,720 Other liabilities — derivatives — 49 — 49 Total liabilities accounted for at fair value $ 195 $ 4,346 $ 2,740 $ 7,281 December 31, 2017 Assets: Available for sale fixed maturities: U.S. Government and government agencies $ 122 $ 112 $ 8 $ 242 States, municipalities and political subdivisions — 6,975 148 7,123 Foreign government — 127 — 127 Residential MBS — 3,105 122 3,227 Commercial MBS — 926 36 962 Asset-backed securities — 7,218 744 7,962 Corporate and other 30 17,662 1,044 18,736 Total AFS fixed maturities 152 36,125 2,102 38,379 Trading fixed maturities 44 304 — 348 Equity securities 1,411 86 165 1,662 Equity index call options — 701 — 701 Assets of managed investment entities 307 4,572 23 4,902 Variable annuity assets (separate accounts) (*) — 644 — 644 Other assets — derivatives — — — — Total assets accounted for at fair value $ 1,914 $ 42,432 $ 2,290 $ 46,636 Liabilities: Liabilities of managed investment entities $ 293 $ 4,372 $ 22 $ 4,687 Derivatives in annuity benefits accumulated — — 2,542 2,542 Other liabilities — derivatives — 35 — 35 Total liabilities accounted for at fair value $ 293 $ 4,407 $ 2,564 $ 7,264 (*) 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, 2018 , 2017 and 2016 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 2018 2017 2016 2018 2017 2016 2018 2017 2016 2018 2017 2016 Perpetual preferred stocks 2 4 6 $ 5 $ 23 $ 35 2 2 7 $ 6 $ 11 $ 28 Common stocks — — 3 — — — — 1 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 Level 3 liabilities. See Note F — “ Derivatives .” Unobservable Input Range Adjustment for insurance subsidiary’s credit risk 0.6% – 2.1% over the risk free rate Risk margin for uncertainty in cash flows 0.73% reduction in the discount rate Surrenders 3% – 23% of indexed account value Partial surrenders 2% – 9% of indexed account value Annuitizations 0.1% – 1% of indexed account value Deaths 1.5% – 9.5% of indexed account value Budgeted option costs 2.6% – 3.6% of indexed account value
Changes in asset balances of Level 3 financial assets	Changes in balances of Level 3 financial assets and liabilities carried at fair value during 2018 , 2017 and 2016 are presented below (in millions). The transfers into and out of Level 3 were due to changes in the availability of market observable inputs and $29 million of equity securities transferred into Level 3 in the first quarter of 2018 related to a small number of limited partnerships and similar investments carried at cost under the prior guidance that are carried at fair value through net earnings under new guidance adopted on January 1, 2018, as discussed in Note A — “ Accounting Policies — Investments .” 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, 2017 Net earnings Other comprehensive income (loss) Purchases and issuances Sales and settlements Transfer into Level 3 Transfer out of Level 3 Balance at December 31, 2018 AFS fixed maturities: U.S. government agency $ 8 $ — $ — $ — $ — $ 1 $ — $ 9 State and municipal 148 — (2 ) — (3 ) — (84 ) 59 Residential MBS 122 (9 ) (4 ) — (21 ) 130 (21 ) 197 Commercial MBS 36 — — 20 — — — 56 Asset-backed securities 744 (3 ) (15 ) 426 (248 ) 82 (139 ) 847 Corporate and other 1,044 (10 ) (18 ) 1,221 (204 ) 27 (64 ) 1,996 Total AFS fixed maturities 2,102 (22 ) (39 ) 1,667 (476 ) 240 (308 ) 3,164 Equity securities 165 9 — 155 (6 ) 30 (17 ) 336 Assets of MIE 23 (8 ) — 6 — — — 21 Total Level 3 assets $ 2,290 $ (21 ) $ (39 ) $ 1,828 $ (482 ) $ 270 $ (325 ) $ 3,521 Embedded derivatives (a) $ (2,542 ) $ 204 $ — $ (545 ) $ 163 $ — $ — $ (2,720 ) Total Level 3 liabilities (b) $ (2,542 ) $ 204 $ — $ (545 ) $ 163 $ — $ — $ (2,720 ) (a) Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $44 million in 2018 . (b) As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets. Total realized/unrealized Balance at December 31, 2016 Net Other Purchases Sales and Transfer Transfer Balance at December 31, 2017 AFS fixed maturities: U.S. government agency $ 8 $ — $ — $ — $ — $ — $ — $ 8 State and municipal 140 — 2 — (2 ) 10 (2 ) 148 Residential MBS 190 (4 ) 2 1 (40 ) 44 (71 ) 122 Commercial MBS 25 2 — 15 (10 ) 4 — 36 Asset-backed securities 484 — 1 410 (132 ) 202 (221 ) 744 Corporate and other 712 (5 ) 2 606 (237 ) 29 (63 ) 1,044 Total AFS fixed maturities 1,559 (7 ) 7 1,032 (421 ) 289 (357 ) 2,102 Equity securities 174 (21 ) 10 38 (16 ) — (20 ) 165 Assets of MIE 29 (11 ) — 9 — — (4 ) 23 Total Level 3 assets $ 1,762 $ (39 ) $ 17 $ 1,079 $ (437 ) $ 289 $ (381 ) $ 2,290 Embedded derivatives (a) $ (1,759 ) $ (589 ) $ — $ (300 ) $ 106 $ — $ — $ (2,542 ) Total Level 3 liabilities (b) $ (1,759 ) $ (589 ) $ — $ (300 ) $ 106 $ — $ — $ (2,542 ) (a) Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $25 million in 2017 . (b) As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets. Total realized/unrealized gains (losses) included in Balance at December 31, 2015 Net earnings Other comprehensive income (loss) Purchases and issuances Sales and settlements Transfer into Level 3 Transfer out of Level 3 Balance at December 31, 2016 AFS fixed maturities: U.S. government agency $ 15 $ (8 ) $ 1 $ — $ — $ — $ — $ 8 State and municipal 89 — (4 ) 57 (2 ) — — 140 Residential MBS 224 (4 ) (2 ) 8 (28 ) 34 (42 ) 190 Commercial MBS 39 (1 ) — — (7 ) — (6 ) 25 Asset-backed securities 470 (1 ) 1 50 (52 ) 60 (44 ) 484 Corporate and other 633 — (10 ) 176 (100 ) 30 (17 ) 712 Total AFS fixed maturities 1,470 (14 ) (14 ) 291 (189 ) 124 (109 ) 1,559 Equity securities 140 (12 ) 35 44 (28 ) 15 (20 ) 174 Assets of MIE 26 (9 ) — 12 — — — 29 Total Level 3 assets $ 1,636 $ (35 ) $ 21 $ 347 $ (217 ) $ 139 $ (129 ) $ 1,762 Embedded derivatives (a) $ (1,369 ) $ (211 ) $ — $ (277 ) $ 98 $ — $ — $ (1,759 ) Total Level 3 liabilities (b) $ (1,369 ) $ (211 ) $ — $ (277 ) $ 98 $ — $ — $ (1,759 ) (a) Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $17 million in 2016 . (b) As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets.
Changes in liability balances of Level 3 financial liabilities	Changes in balances of Level 3 financial assets and liabilities carried at fair value during 2018 , 2017 and 2016 are presented below (in millions). The transfers into and out of Level 3 were due to changes in the availability of market observable inputs and $29 million of equity securities transferred into Level 3 in the first quarter of 2018 related to a small number of limited partnerships and similar investments carried at cost under the prior guidance that are carried at fair value through net earnings under new guidance adopted on January 1, 2018, as discussed in Note A — “ Accounting Policies — Investments .” 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, 2017 Net earnings Other comprehensive income (loss) Purchases and issuances Sales and settlements Transfer into Level 3 Transfer out of Level 3 Balance at December 31, 2018 AFS fixed maturities: U.S. government agency $ 8 $ — $ — $ — $ — $ 1 $ — $ 9 State and municipal 148 — (2 ) — (3 ) — (84 ) 59 Residential MBS 122 (9 ) (4 ) — (21 ) 130 (21 ) 197 Commercial MBS 36 — — 20 — — — 56 Asset-backed securities 744 (3 ) (15 ) 426 (248 ) 82 (139 ) 847 Corporate and other 1,044 (10 ) (18 ) 1,221 (204 ) 27 (64 ) 1,996 Total AFS fixed maturities 2,102 (22 ) (39 ) 1,667 (476 ) 240 (308 ) 3,164 Equity securities 165 9 — 155 (6 ) 30 (17 ) 336 Assets of MIE 23 (8 ) — 6 — — — 21 Total Level 3 assets $ 2,290 $ (21 ) $ (39 ) $ 1,828 $ (482 ) $ 270 $ (325 ) $ 3,521 Embedded derivatives (a) $ (2,542 ) $ 204 $ — $ (545 ) $ 163 $ — $ — $ (2,720 ) Total Level 3 liabilities (b) $ (2,542 ) $ 204 $ — $ (545 ) $ 163 $ — $ — $ (2,720 ) (a) Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $44 million in 2018 . (b) As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets. Total realized/unrealized Balance at December 31, 2016 Net Other Purchases Sales and Transfer Transfer Balance at December 31, 2017 AFS fixed maturities: U.S. government agency $ 8 $ — $ — $ — $ — $ — $ — $ 8 State and municipal 140 — 2 — (2 ) 10 (2 ) 148 Residential MBS 190 (4 ) 2 1 (40 ) 44 (71 ) 122 Commercial MBS 25 2 — 15 (10 ) 4 — 36 Asset-backed securities 484 — 1 410 (132 ) 202 (221 ) 744 Corporate and other 712 (5 ) 2 606 (237 ) 29 (63 ) 1,044 Total AFS fixed maturities 1,559 (7 ) 7 1,032 (421 ) 289 (357 ) 2,102 Equity securities 174 (21 ) 10 38 (16 ) — (20 ) 165 Assets of MIE 29 (11 ) — 9 — — (4 ) 23 Total Level 3 assets $ 1,762 $ (39 ) $ 17 $ 1,079 $ (437 ) $ 289 $ (381 ) $ 2,290 Embedded derivatives (a) $ (1,759 ) $ (589 ) $ — $ (300 ) $ 106 $ — $ — $ (2,542 ) Total Level 3 liabilities (b) $ (1,759 ) $ (589 ) $ — $ (300 ) $ 106 $ — $ — $ (2,542 ) (a) Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $25 million in 2017 . (b) As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets. Total realized/unrealized gains (losses) included in Balance at December 31, 2015 Net earnings Other comprehensive income (loss) Purchases and issuances Sales and settlements Transfer into Level 3 Transfer out of Level 3 Balance at December 31, 2016 AFS fixed maturities: U.S. government agency $ 15 $ (8 ) $ 1 $ — $ — $ — $ — $ 8 State and municipal 89 — (4 ) 57 (2 ) — — 140 Residential MBS 224 (4 ) (2 ) 8 (28 ) 34 (42 ) 190 Commercial MBS 39 (1 ) — — (7 ) — (6 ) 25 Asset-backed securities 470 (1 ) 1 50 (52 ) 60 (44 ) 484 Corporate and other 633 — (10 ) 176 (100 ) 30 (17 ) 712 Total AFS fixed maturities 1,470 (14 ) (14 ) 291 (189 ) 124 (109 ) 1,559 Equity securities 140 (12 ) 35 44 (28 ) 15 (20 ) 174 Assets of MIE 26 (9 ) — 12 — — — 29 Total Level 3 assets $ 1,636 $ (35 ) $ 21 $ 347 $ (217 ) $ 139 $ (129 ) $ 1,762 Embedded derivatives (a) $ (1,369 ) $ (211 ) $ — $ (277 ) $ 98 $ — $ — $ (1,759 ) Total Level 3 liabilities (b) $ (1,369 ) $ (211 ) $ — $ (277 ) $ 98 $ — $ — $ (1,759 ) (a) Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $17 million in 2016 . (b) As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets.
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 Value Value Total Level 1 Level 2 Level 3 2018 Financial assets: Cash and cash equivalents $ 1,515 $ 1,515 $ 1,515 $ — $ — Mortgage loans 1,068 1,056 — — 1,056 Policy loans 174 174 — — 174 Total financial assets not accounted for at fair value $ 2,757 $ 2,745 $ 1,515 $ — $ 1,230 Financial liabilities: Annuity benefits accumulated (*) $ 36,384 $ 34,765 $ — $ — $ 34,765 Long-term debt 1,302 1,231 — 1,228 3 Total financial liabilities not accounted for at fair value $ 37,686 $ 35,996 $ — $ 1,228 $ 34,768 2017 Financial assets: Cash and cash equivalents $ 2,338 $ 2,338 $ 2,338 $ — $ — Mortgage loans 1,125 1,119 — — 1,119 Policy loans 184 184 — — 184 Total financial assets not accounted for at fair value $ 3,647 $ 3,641 $ 2,338 $ — $ 1,303 Financial liabilities: Annuity benefits accumulated (*) $ 33,110 $ 32,461 $ — $ — $ 32,461 Long-term debt 1,301 1,354 — 1,351 3 Total financial liabilities not accounted for at fair value $ 34,411 $ 33,815 $ — $ 1,351 $ 32,464 (*) Excludes $232 million and $206 million of life contingent annuities in the payout phase at December 31, 2018 and 2017 , respectively.

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Available for sale fixed maturities and equity securities	Available for sale fixed maturities at December 31 consisted of the following (in millions): 2018 2017 Amortized Cost Gross Unrealized Net Unrealized Fair Value Amortized Cost Gross Unrealized Net Unrealized Fair Value Gains Losses Gains Losses Fixed maturities: U.S. Government and government agencies $ 235 $ 1 $ (3 ) $ (2 ) $ 233 $ 244 $ 1 $ (3 ) $ (2 ) $ 242 States, municipalities and political subdivisions 6,825 169 (55 ) 114 6,939 6,887 254 (18 ) 236 7,123 Foreign government 140 2 — 2 142 124 3 — 3 127 Residential MBS 2,476 277 (9 ) 268 2,744 2,884 349 (6 ) 343 3,227 Commercial MBS 905 17 (2 ) 15 920 927 36 (1 ) 35 962 Asset-backed securities 9,781 130 (100 ) 30 9,811 7,836 142 (16 ) 126 7,962 Corporate and other 21,475 167 (434 ) (267 ) 21,208 18,136 638 (38 ) 600 18,736 Total fixed maturities $ 41,837 $ 763 $ (603 ) $ 160 $ 41,997 $ 37,038 $ 1,423 $ (82 ) $ 1,341 $ 38,379
Equity securities reported at fair value	As discussed in Note A — “ Accounting Policies — Investments ,” AFG implemented new accounting guidance effective on January 1, 2018, which requires all equity securities previously classified as “available for sale” to be reported at fair value, with holding gains and losses recognized in net earnings. Equity securities reported at fair value consisted of the following at December 31, 2018 (in millions): Fair Value over (under) Actual Cost Fair Value Cost Common stocks $ 1,241 $ 1,148 $ (93 ) Perpetual preferred stocks 705 666 (39 ) Total equity securities carried at fair value $ 1,946 $ 1,814 $ (132 )
Available for sale securities in a continuous unrealized loss position	The following tables show gross unrealized losses (dollars in millions) on available for sale fixed maturities and equity securities by investment category and length of time that individual securities have been in a continuous unrealized loss position at the following balance sheet dates. Less Than Twelve Months Twelve Months or More Unrealized Loss Fair Value Fair Value as % of Cost Unrealized Loss Fair Value Fair Value as % of Cost December 31, 2018 Fixed maturities: U.S. Government and government agencies $ — $ 41 100 % $ (3 ) $ 120 98 % States, municipalities and political subdivisions (23 ) 1,497 98 % (32 ) 902 97 % Foreign government — 18 100 % — 4 100 % Residential MBS (4 ) 279 99 % (5 ) 139 97 % Commercial MBS (1 ) 147 99 % (1 ) 30 97 % Asset-backed securities (77 ) 5,406 99 % (23 ) 629 96 % Corporate and other (306 ) 10,378 97 % (128 ) 2,078 94 % Total fixed maturities $ (411 ) $ 17,766 98 % $ (192 ) $ 3,902 95 % December 31, 2017 Fixed maturities: U.S. Government and government agencies $ — $ 55 100 % $ (3 ) $ 123 98 % States, municipalities and political subdivisions (8 ) 825 99 % (10 ) 431 98 % Foreign government — 4 100 % — — — % Residential MBS (1 ) 118 99 % (5 ) 118 96 % Commercial MBS (1 ) 67 99 % — — — % Asset-backed securities (7 ) 1,195 99 % (9 ) 299 97 % Corporate and other (20 ) 2,031 99 % (18 ) 603 97 % Total fixed maturities $ (37 ) $ 4,295 99 % $ (45 ) $ 1,574 97 % Equity securities: Common stocks $ (22 ) $ 117 84 % $ — $ — — % Perpetual preferred stocks — 41 100 % (1 ) 13 93 % Total equity securities $ (22 ) $ 158 88 % $ (1 ) $ 13 93 %
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): 2018 2017 2016 Balance at January 1 $ 145 $ 153 $ 160 Additional credit impairments on: Previously impaired securities 1 1 2 Securities without prior impairments 1 3 1 Reductions due to sales or redemptions (5 ) (12 ) (10 ) Balance at December 31 $ 142 $ 145 $ 153
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, 2018 (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 $ 1,310 $ 1,318 3 % After one year through five years 8,521 8,554 20 % After five years through ten years 14,235 14,044 34 % After ten years 4,609 4,606 11 % 28,675 28,522 68 % ABS (average life of approximately 4.5 years) 9,781 9,811 23 % MBS (average life of approximately 4.5 years) 3,381 3,664 9 % Total $ 41,837 $ 41,997 100 %
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 Net December 31, 2018 Net unrealized gain on: Fixed maturities — annuity segment (a) $ 101 $ (21 ) $ 80 Fixed maturities — all other 59 (13 ) 46 Total fixed maturities 160 (34 ) 126 Deferred policy acquisition costs — annuity segment (42 ) 9 (33 ) Annuity benefits accumulated (14 ) 3 (11 ) Unearned revenue 1 — 1 Total net unrealized gain on marketable securities $ 105 $ (22 ) $ 83 December 31, 2017 Net unrealized gain on: Fixed maturities — annuity segment (a) $ 1,082 $ (227 ) $ 855 Fixed maturities — all other 259 (55 ) 204 Total fixed maturities 1,341 (282 ) 1,059 Equity securities (b) 279 (58 ) 221 Total investments 1,620 (340 ) 1,280 Deferred policy acquisition costs — annuity segment (433 ) 91 (342 ) Annuity benefits accumulated (137 ) 29 (108 ) Unearned revenue 13 (3 ) 10 Total net unrealized gain on marketable securities $ 1,063 $ (223 ) $ 840 (a) Net unrealized gains on fixed maturity investments supporting AFG’s annuity benefits accumulated. (b) As discussed in Note A — “ Accounting Policies — Investments ,” effective January 1, 2018, all equity securities other than those accounted for under the equity method are carried at fair value through net earnings.
Net investment income earned and investment expenses incurred	The following table shows (in millions) investment income earned and investment expenses incurred. 2018 2017 2016 Investment income: Fixed maturities $ 1,742 $ 1,607 $ 1,510 Equity securities: Dividends 79 73 77 Change in fair value (*) 22 6 4 Equity in earnings of partnerships and similar investments 161 64 44 Other 112 102 81 Gross investment income 2,116 1,852 1,716 Investment expenses (22 ) (21 ) (20 ) Net investment income $ 2,094 $ 1,831 $ 1,696 (*) As discussed in Note A — “ Accounting Policies — Investments ,” AFG adopted guidance in January 2018 that requires all equity securities other than those accounted for under the equity method to be reported at fair value with holding gains and losses recognized in net earnings. Although the change in the fair value of the majority of AFG’s equity securities is recorded in realized gains (losses) on securities, AFG records holding gains and losses in net investment income on equity securities classified as “trading” under the previous guidance and on a small portfolio of limited partnership and similar investments that do not qualify for the equity method of accounting.
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) included in AOCI related to fixed maturity and equity security investments are summarized as follows (in millions): 2018 2017 Realized gains (losses) Realized gains (losses) Before Impairments Impairments Total Change in Unrealized Before Impairments Impairments Total Change in Unrealized Fixed maturities $ 6 $ (26 ) $ (20 ) $ (1,181 ) $ 17 $ (20 ) $ (3 ) $ 532 Equity securities (265 ) — (265 ) — 70 (64 ) 6 128 Mortgage loans and other investments 1 — 1 — (6 ) (4 ) (10 ) — Other (*) 11 7 18 502 (3 ) 15 12 (219 ) Total pretax (247 ) (19 ) (266 ) (679 ) 78 (73 ) 5 441 Tax effects: Reclassify impact of U.S. corporate tax rate change — — — — — — — 149 Other 52 4 56 143 (27 ) 25 (2 ) (154 ) Total tax effects 52 4 56 143 (27 ) 25 (2 ) (5 ) Net of tax $ (195 ) $ (15 ) $ (210 ) $ (536 ) $ 51 $ (48 ) $ 3 $ 436 2016 Realized gains (losses) Before Impairments Impairments Total Change in Unrealized Fixed maturities $ 36 $ (38 ) $ (2 ) $ 90 Equity securities 106 (93 ) 13 67 Other (*) (7 ) 15 8 (52 ) Total pretax 135 (116 ) 19 105 Tax effects (48 ) 41 (7 ) (37 ) Noncontrolling interests (2 ) 3 1 4 Net of tax and noncontrolling interests $ 85 $ (72 ) $ 13 $ 72 (*) Primarily adjustments to deferred policy acquisition costs and reserves related to the annuity business.
Holding gains (losses) on equity securities still held	As discussed in Note A — “ Accounting Policies — Investments ,” effective January 1, 2018, all equity securities other than those accounted for under the equity method are carried at fair value through net earnings. AFG recorded net holding gains (losses) on equity securities during 2018 on securities that were still owned at December 31, 2018 as follows (in millions): 2018 Included in realized gains (losses) $ (279 ) Included in net investment income 22 $ (257 )
Gross realized gains and losses on available for sale fixed maturity and equity security investments	Gross realized gains and losses (excluding impairment write-downs and mark-to-market of derivatives) on available for sale fixed maturity investment transactions consisted of the following (in millions): 2018 2017 2016 Fixed maturities: Gross gains $ 22 $ 43 $ 55 Gross losses (14 ) (20 ) (10 )

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2018
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): December 31, 2018 December 31, 2017 Derivative Balance Sheet Line Asset Liability Asset Liability MBS with embedded derivatives Fixed maturities $ 109 $ — $ 105 $ — Public company warrants Equity securities — — 4 — Fixed-indexed and variable-indexed annuities (embedded derivative) Annuity benefits accumulated — 2,720 — 2,542 Equity index call options Equity index call options 184 — 701 — Equity index put options Other liabilities — 1 — — Reinsurance contract (embedded derivative) Other liabilities — 2 — 4 $ 293 $ 2,723 $ 810 $ 2,546
Summary of gain (loss) included in the Statement of Earnings for changes in the fair value of derivatives	The following table summarizes the gains (losses) included in AFG’s Statement of Earnings for changes in the fair value of derivatives that do not qualify for hedge accounting for 2018 , 2017 and 2016 (in millions): Derivative Statement of Earnings Line 2018 2017 2016 MBS with embedded derivatives Realized gains (losses) on securities $ (7 ) $ (6 ) $ (9 ) Public company warrants Realized gains (losses) on securities (3 ) — — Fixed-indexed and variable-indexed annuities (embedded derivative) (*) Annuity benefits 204 (589 ) (211 ) Equity index call options Annuity benefits (298 ) 494 141 Equity index put options Annuity benefits (1 ) — — Reinsurance contracts (embedded derivative) Net investment income 2 (2 ) (1 ) $ (103 ) $ (103 ) $ (80 ) (*) The change in fair value of the embedded derivative includes losses related to unlocking of actuarial assumptions of $44 million in 2018 , $25 million in 2017 and $17 million in 2016 .

Deferred Policy Acquisition C_2

Deferred Policy Acquisition Costs (Tables)	12 Months Ended
	Dec. 31, 2018
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 Run-off Long-term Care and Life Deferred Deferred Sales Consolidated Costs Costs Inducements PVFP Subtotal Unrealized (*) Total Total Balance at December 31, 2015 $ 226 $ 1,018 $ 119 $ 55 $ 1,192 $ (234 ) $ 958 $ 1,184 Additions 535 230 9 — 239 — 239 774 Amortization: Periodic amortization (520 ) (169 ) (24 ) (9 ) (202 ) — (202 ) (722 ) Annuity unlocking — 25 4 — 29 — 29 29 Included in realized gains — 6 2 — 8 — 8 8 Foreign currency translation (3 ) — — — — — — (3 ) Change in unrealized — — — — — (31 ) (31 ) (31 ) Balance at December 31, 2016 238 1,110 110 46 1,266 (265 ) 1,001 1,239 Additions 588 225 4 — 229 — 229 817 Amortization: Periodic amortization (556 ) (161 ) (19 ) (8 ) (188 ) — (188 ) (744 ) Annuity unlocking — 34 6 1 41 — 41 41 Included in realized gains — 9 1 — 10 — 10 10 Foreign currency translation — — — — — — — — Other — — — 10 10 — 10 10 Change in unrealized — — — — — (157 ) (157 ) (157 ) Balance at December 31, 2017 270 1,217 102 49 1,368 (422 ) 946 1,216 Additions 675 263 2 — 265 — 265 940 Amortization: Periodic amortization (644 ) (238 ) (19 ) (7 ) (264 ) — (264 ) (908 ) Annuity unlocking — 29 — — 29 — 29 29 Included in realized gains — 14 1 — 15 — 15 15 Foreign currency translation (2 ) — — — — — — (2 ) Change in unrealized — — — — — 392 392 392 Balance at December 31, 2018 $ 299 $ 1,285 $ 86 $ 42 $ 1,413 $ (30 ) $ 1,383 $ 1,682 (*) Adjustments to DPAC related to net unrealized gains/losses on securities and cash flow hedges.

Managed Investment Entities (Ta

Managed Investment Entities (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 2017 2016 Investment in CLO tranches $ 188 $ 215 $ 216 Gains (losses) on change in fair value of assets/liabilities (a): Assets (189 ) (8 ) 131 Liabilities 168 20 (116 ) Management fees paid to AFG 16 18 17 CLO earnings attributable to AFG Shareholders (b) 7 23 37 (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 Intangibles

Goodwill and Other Intangibles (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in the carrying value of goodwill by reporting segment	Changes in the carrying value of goodwill during 2016 , 2017 and 2018 , by reporting segment, are presented in the following table (in millions): Property and Casualty Annuity Total Balance at January 1, 2016, December 31, 2016 and December 31, 2017 $ 168 $ 31 $ 199 Acquisition of subsidiary in 2018 8 — 8 Balance at December 31, 2018 $ 176 $ 31 $ 207

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of long-term debt instruments	Long-term debt consisted of the following at December 31 (in millions): 2018 2017 Principal Discount and Issue Costs Carrying Value Principal Discount and Issue Costs Carrying Value Direct Senior Obligations of AFG: 4.50% Senior Notes due June 2047 $ 590 $ (2 ) $ 588 $ 590 $ (2 ) $ 588 3.50% Senior Notes due August 2026 425 (4 ) 421 425 (5 ) 420 Other 3 — 3 3 — 3 1,018 (6 ) 1,012 1,018 (7 ) 1,011 Direct Subordinated Obligations of AFG: 6-1/4% Subordinated Debentures due September 2054 150 (5 ) 145 150 (5 ) 145 6% Subordinated Debentures due November 2055 150 (5 ) 145 150 (5 ) 145 300 (10 ) 290 300 (10 ) 290 $ 1,318 $ (16 ) $ 1,302 $ 1,318 $ (17 ) $ 1,301

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Stockholders' Equity Note [Abstract]
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, 2018 759,035 $ 73.40 Granted 200,625 $ 112.86 Vested (86,177 ) $ 56.89 Forfeited (7,553 ) $ 87.47 Outstanding at December 31, 2018 865,930 $ 84.06
Summary of stock options activity	Data for stock options issued under AFG’s stock incentive plans is presented below: Shares Average Exercise Price Average Remaining Contractual Term Aggregate Intrinsic Value (in millions) Outstanding at January 1, 2018 3,467,340 $ 45.80 Exercised (778,270 ) $ 37.66 Forfeited/Cancelled (21,628 ) $ 42.10 Outstanding at December 31, 2018 2,667,442 $ 48.20 4.2 years $ 113 Options exercisable at December 31, 2018 2,253,003 $ 45.95 3.9 years $ 100
Components of accumulated other comprehensive income (loss)	The progression of the components of accumulated other comprehensive income follows (in millions): Other Comprehensive Income (Loss) AOCI Beginning Balance Pretax Tax Net of tax Attributable to noncontrolling interests Attributable to shareholders Other (c) AOCI Ending Balance Year ended December 31, 2018 Net unrealized gains (losses) on securities: Unrealized holding losses on securities arising during the period $ (689 ) $ 145 $ (544 ) $ — $ (544 ) Reclassification adjustment for realized (gains) losses included in net earnings (a) 10 (2 ) 8 — 8 Total net unrealized gains (losses) on securities (b) $ 840 (679 ) 143 (536 ) — (536 ) $ (221 ) $ 83 Net unrealized gains (losses) on cash flow hedges (13 ) 2 — 2 — 2 — (11 ) Foreign currency translation adjustments (6 ) (9 ) (1 ) (10 ) — (10 ) — (16 ) Pension and other postretirement plans adjustments (8 ) — — — — — — (8 ) Total $ 813 $ (686 ) $ 142 $ (544 ) $ — $ (544 ) $ (221 ) $ 48 Year ended December 31, 2017 Net unrealized gains on securities: Unrealized holding gains on securities arising during the period $ 456 $ (159 ) $ 297 $ — $ 297 Reclassification adjustment for realized (gains) losses included in net earnings (a) (15 ) 5 (10 ) — (10 ) Total net unrealized gains on securities (b) $ 404 441 (154 ) 287 — 287 $ 149 $ 840 Net unrealized losses on cash flow hedges (7 ) (6 ) 2 (4 ) — (4 ) (2 ) (13 ) Foreign currency translation adjustments (15 ) 9 3 12 — 12 (3 ) (6 ) Pension and other postretirement plans adjustments (7 ) 1 — 1 — 1 (2 ) (8 ) Total $ 375 $ 445 $ (149 ) $ 296 $ — $ 296 $ 142 $ 813 Year ended December 31, 2016 Net unrealized gains on securities: Unrealized holding gains on securities arising during the period $ 124 $ (44 ) $ 80 $ (4 ) $ 76 Reclassification adjustment for realized (gains) losses included in net earnings (a) (19 ) 7 (12 ) (1 ) (13 ) Total net unrealized gains on securities (b) $ 332 105 (37 ) 68 (5 ) 63 $ 9 $ 404 Net unrealized gains (losses) on cash flow hedges 1 (12 ) 4 (8 ) — (8 ) — (7 ) Foreign currency translation adjustments (22 ) 6 1 7 — 7 — (15 ) Pension and other postretirement plans adjustments (7 ) — — — — — — (7 ) Total $ 304 $ 99 $ (32 ) $ 67 $ (5 ) $ 62 $ 9 $ 375 (a) The reclassification adjustment out of net unrealized gains on securities affected the following lines in AFG’s Statement of Earnings: OCI component Affected line in the statement of earnings Pretax Realized gains (losses) on securities Tax Provision for income taxes Attributable to noncontrolling interests Net earnings attributable to noncontrolling interests (b) Includes net unrealized gains of $58 million at December 31, 2018 compared to net unrealized gains of $68 million and $52 million at December 31, 2017 and 2016 , related to securities for which only the credit portion of an other-than-temporary impairment has been recorded in earnings. (c) On January 1, 2018, AFG adopted new guidance that requires all equity securities other than those accounted for under the equity method to be reported at fair value with holding gains and losses recognized in net earnings. At the date of adoption, the $221 million net unrealized gain on equity securities classified as available for sale (with unrealized holding gains and losses reported in AOCI) under the prior guidance was reclassified from AOCI to retained earnings as the cumulative effect of an accounting change. Other also includes the December 2017 reclassification of $145 million stranded in AOCI from accounting for the Tax Cuts and Jobs Act of 2017 to retained earnings (see Note A — “ Accounting Policies — Income Taxes ”) , the impact on AOCI of the December 2017 sale of redeemable noncontrolling interests in Neon and the November 2016 acquisition of the noncontrolling interest in NATL (see Note B — “ Acquisitions and Sale of Businesses ”).

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
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 ( 21% in 2018 and 35% in both 2017 and 2016) to the provision for income taxes as shown in AFG’s Statement of Earnings (dollars in millions): 2018 2017 2016 Amount % of EBT Amount % of EBT Amount % of EBT Earnings before income taxes (“EBT”) $ 639 $ 724 $ 787 Income taxes at statutory rate $ 134 21 % $ 253 35 % $ 275 35 % Effect of: Tax exempt interest (13 ) (2 %) (23 ) (3 %) (24 ) (3 %) Adjustment to prior year taxes (8 ) (1 %) (4 ) (1 %) (2 ) — % Stock-based compensation (8 ) (1 %) (16 ) (2 %) (9 ) (1 %) Dividend received deduction (4 ) (1 %) (8 ) (1 %) (7 ) (1 %) Employee stock ownership plan dividend paid deduction (3 ) (1 %) (5 ) (1 %) (2 ) — % Foreign operations (2 ) — % 21 3 % 5 — % Change in valuation allowance (excluding change in tax rate) 11 2 % (7 ) (1 %) 52 7 % Nondeductible expenses 7 1 % 6 1 % 7 1 % Neon restructuring — — % (56 ) (8 %) (111 ) (14 %) Change in U.S corporate tax rate — — % 83 11 % — — % Acquisition of noncontrolling interest in NATL — — % — — % (66 ) (8 %) Subsidiaries not in AFG’s tax return — — % — — % 3 — % Other 8 1 % 3 1 % (2 ) (1 %) Provision for income taxes as shown in the statement of earnings $ 122 19 % $ 247 34 % $ 119 15 %
Components of income tax provision (credit)	The total income tax provision (credit) consists of (in millions): 2018 2017 2016 Current taxes: Federal $ 196 $ 153 $ 299 State 8 6 12 Deferred taxes: Federal (82 ) 5 (192 ) Impact of change in U.S. corporate tax rate — 83 — Total Federal deferred taxes (82 ) 88 (192 ) Provision for income taxes $ 122 $ 247 $ 119
Summary of operating loss carryforwards	For income tax purposes, AFG and its subsidiaries had the following carryforwards available at December 31, 2018 (in millions): Expiring Amount Operating Loss – U.S. 2019 - 2022 $ 112 Operating Loss – United Kingdom indefinite 215 (*) (*) £168 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 AFG’s Balance Sheet at December 31 were as follows (in millions): 2018 2017 Excluding Unrealized Gains Impact of Unrealized Gains Total Excluding Unrealized Gains Impact of Unrealized Gains Total Deferred tax assets: Federal net operating loss carryforwards $ 23 $ — $ 23 $ 27 $ — $ 27 Foreign underwriting losses 93 — 93 80 — 80 Capital loss carryforwards — — — 32 — 32 Insurance claims and reserves 740 3 743 665 29 694 Employee benefits 88 — 88 84 — 84 Other, net 44 — 44 48 (3 ) 45 Total deferred tax assets before valuation allowance 988 3 991 936 26 962 Valuation allowance against deferred tax assets (119 ) — (119 ) (109 ) — (109 ) Total deferred tax assets 869 3 872 827 26 853 Deferred tax liabilities: Investment securities (36 ) (34 ) (70 ) (1 ) (340 ) (341 ) Deferred policy acquisition costs (300 ) 9 (291 ) (293 ) 91 (202 ) Insurance claims and reserves transition liability (110 ) — (110 ) (128 ) — (128 ) Real estate, property and equipment (36 ) — (36 ) (35 ) — (35 ) Total deferred tax liabilities (482 ) (25 ) (507 ) (457 ) (249 ) (706 ) Net deferred tax asset (liability) $ 387 $ (22 ) $ 365 $ 370 $ (223 ) $ 147
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): 2018 2017 2016 Balance at January 1 $ — $ 1 $ 1 Additions for tax positions of prior years — — — Reductions for tax positions of prior years — — — Additions for tax positions of current year — — — Settlements — (1 ) — Balance at December 31 $ — $ — $ 1

Quarterly Operating Results (_2

Quarterly Operating Results (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 (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 Quarter 2nd Quarter 3rd Quarter 4th Quarter Total Year 2018 Revenues $ 1,619 $ 1,833 $ 2,008 $ 1,690 $ 7,150 Net earnings (losses), including noncontrolling interests 141 208 203 (35 ) 517 Net earnings (losses) attributable to shareholders 145 210 204 (29 ) 530 Earnings (losses) attributable to shareholders per Common Share: Basic $ 1.64 $ 2.36 $ 2.30 $ (0.33 ) $ 5.95 Diluted 1.60 2.31 2.26 (0.33 ) 5.85 Average number of Common Shares: Basic 88.6 89.0 89.1 89.3 89.0 Diluted 90.4 90.7 90.7 89.3 90.6 2017 Revenues $ 1,576 $ 1,646 $ 1,835 $ 1,808 $ 6,865 Net earnings, including noncontrolling interests 155 145 11 166 477 Net earnings attributable to shareholders 153 145 11 166 475 Earnings attributable to shareholders per Common Share: Basic $ 1.76 $ 1.64 $ 0.13 $ 1.88 $ 5.40 Diluted 1.72 1.61 0.13 1.84 5.28 Average number of Common Shares: Basic 87.2 87.8 88.1 88.2 87.8 Diluted 89.3 89.8 90.0 90.1 89.8
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), favorable (adverse) prior year development of AFG’s liability for losses and loss adjustment expenses (“LAE”) and the impact of derivatives related to fixed-indexed and variable-indexed annuities (“FIAs”) were as follows (in millions): 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total Year Realized Gains (Losses) on Securities and Subsidiaries 2018 – change in fair value of equity securities $ (95 ) $ 23 $ 33 $ (223 ) $ (262 ) 2018 – other realized gains (losses) 2 8 1 (15 ) (4 ) 2017 3 8 (12 ) 6 5 Prior Year Development Favorable (Adverse) 2018 $ 56 $ 44 $ 31 $ 61 $ 192 2017 28 22 (52 ) 66 64 Impact of Derivatives related to FIAs Favorable (Adverse) 2018 $ 13 $ 3 $ (2 ) $ (47 ) $ (33 ) 2017 (2 ) (16 ) (4 ) (11 ) (33 )

Insurance (Tables)

Insurance (Tables)	12 Months Ended
	Dec. 31, 2018
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 over the past three years (in millions): 2018 2017 2016 Balance at beginning of period $ 9,678 $ 8,563 $ 8,127 Less reinsurance recoverables, net of allowance 2,957 2,302 2,201 Net liability at beginning of period 6,721 6,261 5,926 Provision for losses and LAE occurring in the current year 3,195 3,019 2,730 Net increase (decrease) in the provision for claims of prior years: Special A&E charges 18 89 36 Neon exited lines charge — (18 ) 57 Other (210 ) (135 ) (61 ) Total losses and LAE incurred 3,003 2,955 2,762 Payments for losses and LAE of: Current year (963 ) (942 ) (841 ) Prior years (1,639 ) (1,586 ) (1,512 ) Total payments (2,602 ) (2,528 ) (2,353 ) Reserves of businesses disposed (*) (319 ) — (40 ) Foreign currency translation and other (4 ) 33 (34 ) Net liability at end of period 6,799 6,721 6,261 Add back reinsurance recoverables, net of allowance 2,942 2,957 2,302 Gross unpaid losses and LAE included in the balance sheet $ 9,741 $ 9,678 $ 8,563 (*) Reflects the reinsurance to close transactions at Neon (discussed below).
Short-duration insurance contracts, reconciliation of claims development to liability	A reconciliation of incurred and paid claims development information to the aggregate carrying amount of the liability for unpaid losses and LAE, with separate disclosure of reinsurance recoverables on unpaid claims is shown below (in millions): 2018 Unpaid losses and allocated LAE, net of reinsurance: Specialty Property and transportation $ 1,117 Specialty casualty 3,884 Specialty financial 225 Other specialty 280 Total Specialty (excluding foreign reserves) 5,506 Other reserves Reserves for foreign operations: Neon Lloyd’s business 265 Other subsidiaries 268 A&E reserves 395 Unallocated LAE 335 Other 30 Total other reserves 1,293 Total reserves, net of reinsurance 6,799 Add back reinsurance recoverables, net of allowance 2,942 Gross unpaid losses and LAE included in the balance sheet $ 9,741
Short-duration insurance contracts, claims development	The following claims development tables and associated disclosures related to short-duration insurance contracts are prepared by sub-segment within the property and casualty insurance business for the most recent 10 accident years. AFG determines its claim counts at the claimant or policy feature level depending on the particular facts and circumstances of the underlying claim. While the methodology is generally consistent within each sub-segment, there are minor differences between and within the sub-segments. The methods used to summarize claim counts have not changed significantly over the time periods reported in the tables below. Property and transportation (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 503 $ 487 $ 505 $ 498 $ 494 $ 494 $ 491 $ 491 $ 491 $ 490 $ 2 138,248 2010 680 640 646 654 656 657 661 659 657 3 138,235 2011 816 803 819 833 844 856 853 850 6 139,345 2012 875 866 880 892 905 900 897 13 145,636 2013 894 881 884 890 890 890 18 141,293 2014 856 842 831 834 831 25 136,259 2015 831 794 789 789 36 134,484 2016 762 730 733 74 122,623 2017 904 868 128 140,963 2018 952 277 119,817 Total $ 7,957 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (a) 2009 $ 219 $ 333 $ 397 $ 440 $ 462 $ 476 $ 480 $ 481 $ 484 $ 485 99.0 % 2010 316 487 536 597 627 638 643 648 650 98.9 % 2011 367 670 732 777 810 828 836 839 98.7 % 2012 574 715 780 826 852 866 892 99.4 % 2013 440 710 769 814 843 859 96.5 % 2014 332 638 702 756 784 94.3 % 2015 361 587 675 717 90.9 % 2016 296 528 590 80.5 % 2017 383 648 74.7 % 2018 399 41.9 % Total $ 6,863 Unpaid losses and LAE — years 2009 through 2018 1,094 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) 23 Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 1,117 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 46.2 % 28.7 % 8.6 % 6.5 % 3.7 % 2.0 % 1.4 % 0.4 % 0.5 % 0.2 % Cumulative 46.2 % 74.9 % 83.5 % 90.0 % 93.7 % 95.7 % 97.1 % 97.5 % 98.0 % 98.2 % (a) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Specialty casualty (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 888 $ 887 $ 864 $ 844 $ 833 $ 828 $ 829 $ 824 $ 820 $ 811 $ 34 56,985 2010 870 886 887 865 879 868 867 864 853 47 56,411 2011 847 845 833 842 827 822 819 811 52 53,385 2012 890 883 876 876 872 867 838 64 51,885 2013 956 938 933 928 933 913 99 51,620 2014 1,023 994 994 992 966 139 54,494 2015 1,068 1,033 1,031 1,030 185 55,468 2016 1,115 1,108 1,097 313 53,038 2017 1,196 1,200 539 52,658 2018 1,257 705 48,996 Total $ 9,776 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (a) 2009 $ 170 $ 381 $ 510 $ 591 $ 653 $ 691 $ 715 $ 731 $ 740 $ 748 92.2 % 2010 191 411 559 644 699 735 756 770 782 91.7 % 2011 172 380 517 606 655 687 707 725 89.4 % 2012 171 378 508 611 674 713 735 87.7 % 2013 180 388 545 656 717 754 82.6 % 2014 187 406 565 668 741 76.7 % 2015 176 406 569 692 67.2 % 2016 184 411 571 52.1 % 2017 196 414 34.5 % 2018 207 16.5 % Total $ 6,369 Unpaid losses and LAE — years 2009 through 2018 3,407 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) 477 Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 3,884 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 19.1 % 23.2 % 16.2 % 11.1 % 7.0 % 4.3 % 2.6 % 1.9 % 1.3 % 1.0 % Cumulative 19.1 % 42.3 % 58.5 % 69.6 % 76.6 % 80.9 % 83.5 % 85.4 % 86.7 % 87.7 % (a) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Specialty financial (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 192 $ 192 $ 186 $ 184 $ 188 $ 186 $ 187 $ 186 $ 185 $ 186 $ 1 27,431 2010 138 145 132 132 135 133 130 127 126 1 21,922 2011 138 157 155 153 147 144 143 139 6 16,368 2012 163 163 151 139 137 135 132 6 21,064 2013 140 145 137 131 127 126 9 28,449 2014 146 157 156 153 147 9 29,411 2015 156 160 158 153 16 37,483 2016 179 184 187 24 44,820 2017 212 215 34 46,921 2018 212 79 36,606 Total $ 1,623 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (a) 2009 $ 112 $ 145 $ 157 $ 166 $ 171 $ 181 $ 185 $ 186 $ 186 $ 185 99.5 % 2010 61 93 104 122 132 130 128 126 126 100.0 % 2011 58 111 115 123 130 131 131 132 95.0 % 2012 71 104 109 117 121 126 128 97.0 % 2013 70 100 107 113 117 117 92.9 % 2014 62 109 125 128 137 93.2 % 2015 72 110 129 133 86.9 % 2016 88 141 158 84.5 % 2017 120 169 78.6 % 2018 112 52.8 % Total $ 1,397 Unpaid losses and LAE — years 2009 through 2018 226 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) (1 ) Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 225 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 50.5 % 26.4 % 7.5 % 5.8 % 4.7 % 1.7 % 0.5 % (0.1 %) — % (0.5 %) Cumulative 50.5 % 76.9 % 84.4 % 90.2 % 94.9 % 96.6 % 97.1 % 97.0 % 97.0 % 96.5 % (a) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Other specialty (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims (a) Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 41 $ 41 $ 41 $ 40 $ 37 $ 37 $ 36 $ 38 $ 33 $ 32 $ 6 — 2010 36 39 40 39 40 40 40 40 40 3 — 2011 39 43 42 43 43 44 44 43 3 — 2012 42 40 39 40 41 39 39 6 — 2013 46 47 46 47 50 53 2 — 2014 58 57 59 59 60 13 — 2015 59 60 63 66 8 — 2016 61 61 65 21 — 2017 63 65 36 — 2018 86 62 — Total $ 549 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (b) 2009 $ 8 $ 12 $ 15 $ 19 $ 22 $ 22 $ 24 $ 26 $ 25 $ 27 84.4 % 2010 8 14 21 24 27 33 35 36 37 92.5 % 2011 12 20 25 28 34 36 37 38 88.4 % 2012 8 17 21 25 28 30 30 76.9 % 2013 7 16 22 34 37 44 83.0 % 2014 13 21 30 36 43 71.7 % 2015 10 26 31 50 75.8 % 2016 9 19 31 47.7 % 2017 10 19 29.2 % 2018 12 14.0 % Total $ 331 Unpaid losses and LAE — years 2009 through 2018 218 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) 62 Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 280 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 18.7 % 17.0 % 12.6 % 14.1 % 9.3 % 7.6 % 3.4 % 3.7 % (0.3 %) 6.3 % Cumulative 18.7 % 35.7 % 48.3 % 62.4 % 71.7 % 79.3 % 82.7 % 86.4 % 86.1 % 92.4 % (a) The amounts shown in Other specialty represent business assumed by AFG’s internal reinsurance program from the operations that make up AFG’s other Specialty property and casualty insurance sub-segments. Accordingly, the liability for incurred claims and allocated LAE represents additional reserves held on claims counted in the tables provided for the other sub-segments (above). (b) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Total Specialty Group (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 1,624 $ 1,607 $ 1,596 $ 1,566 $ 1,552 $ 1,545 $ 1,543 $ 1,539 $ 1,529 $ 1,519 $ 43 222,664 2010 1,724 1,710 1,705 1,690 1,710 1,698 1,698 1,690 1,676 54 216,568 2011 1,840 1,848 1,849 1,871 1,861 1,866 1,859 1,843 67 209,098 2012 1,970 1,952 1,946 1,947 1,955 1,941 1,906 89 218,585 2013 2,036 2,011 2,000 1,996 2,000 1,982 128 221,362 2014 2,083 2,050 2,040 2,038 2,004 186 220,164 2015 2,114 2,047 2,041 2,038 245 227,435 2016 2,117 2,083 2,082 432 220,481 2017 2,375 2,348 737 240,542 2018 2,507 1,123 205,419 Total $ 19,905 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (a) 2009 $ 509 $ 871 $ 1,079 $ 1,216 $ 1,308 $ 1,370 $ 1,404 $ 1,424 $ 1,435 $ 1,445 95.1 % 2010 576 1,005 1,220 1,387 1,485 1,536 1,562 1,580 1,595 95.2 % 2011 609 1,181 1,389 1,534 1,629 1,682 1,711 1,734 94.1 % 2012 824 1,214 1,418 1,579 1,675 1,735 1,785 93.7 % 2013 697 1,214 1,443 1,617 1,714 1,774 89.5 % 2014 594 1,174 1,422 1,588 1,705 85.1 % 2015 619 1,129 1,404 1,592 78.1 % 2016 577 1,099 1,350 64.8 % 2017 709 1,250 53.2 % 2018 730 29.1 % Total $ 14,960 Unpaid losses and LAE — years 2009 through 2018 4,945 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) 561 Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 5,506 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 32.6 % 25.5 % 12.2 % 8.8 % 5.5 % 3.2 % 2.0 % 1.2 % 0.8 % 0.7 % Cumulative 32.6 % 58.1 % 70.3 % 79.1 % 84.6 % 87.8 % 89.8 % 91.0 % 91.8 % 92.5 % (a) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ).
Short-duration insurance contracts, schedule of historical claims duration	The following claims development tables and associated disclosures related to short-duration insurance contracts are prepared by sub-segment within the property and casualty insurance business for the most recent 10 accident years. AFG determines its claim counts at the claimant or policy feature level depending on the particular facts and circumstances of the underlying claim. While the methodology is generally consistent within each sub-segment, there are minor differences between and within the sub-segments. The methods used to summarize claim counts have not changed significantly over the time periods reported in the tables below. Property and transportation (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 503 $ 487 $ 505 $ 498 $ 494 $ 494 $ 491 $ 491 $ 491 $ 490 $ 2 138,248 2010 680 640 646 654 656 657 661 659 657 3 138,235 2011 816 803 819 833 844 856 853 850 6 139,345 2012 875 866 880 892 905 900 897 13 145,636 2013 894 881 884 890 890 890 18 141,293 2014 856 842 831 834 831 25 136,259 2015 831 794 789 789 36 134,484 2016 762 730 733 74 122,623 2017 904 868 128 140,963 2018 952 277 119,817 Total $ 7,957 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (a) 2009 $ 219 $ 333 $ 397 $ 440 $ 462 $ 476 $ 480 $ 481 $ 484 $ 485 99.0 % 2010 316 487 536 597 627 638 643 648 650 98.9 % 2011 367 670 732 777 810 828 836 839 98.7 % 2012 574 715 780 826 852 866 892 99.4 % 2013 440 710 769 814 843 859 96.5 % 2014 332 638 702 756 784 94.3 % 2015 361 587 675 717 90.9 % 2016 296 528 590 80.5 % 2017 383 648 74.7 % 2018 399 41.9 % Total $ 6,863 Unpaid losses and LAE — years 2009 through 2018 1,094 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) 23 Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 1,117 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 46.2 % 28.7 % 8.6 % 6.5 % 3.7 % 2.0 % 1.4 % 0.4 % 0.5 % 0.2 % Cumulative 46.2 % 74.9 % 83.5 % 90.0 % 93.7 % 95.7 % 97.1 % 97.5 % 98.0 % 98.2 % (a) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Specialty casualty (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 888 $ 887 $ 864 $ 844 $ 833 $ 828 $ 829 $ 824 $ 820 $ 811 $ 34 56,985 2010 870 886 887 865 879 868 867 864 853 47 56,411 2011 847 845 833 842 827 822 819 811 52 53,385 2012 890 883 876 876 872 867 838 64 51,885 2013 956 938 933 928 933 913 99 51,620 2014 1,023 994 994 992 966 139 54,494 2015 1,068 1,033 1,031 1,030 185 55,468 2016 1,115 1,108 1,097 313 53,038 2017 1,196 1,200 539 52,658 2018 1,257 705 48,996 Total $ 9,776 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (a) 2009 $ 170 $ 381 $ 510 $ 591 $ 653 $ 691 $ 715 $ 731 $ 740 $ 748 92.2 % 2010 191 411 559 644 699 735 756 770 782 91.7 % 2011 172 380 517 606 655 687 707 725 89.4 % 2012 171 378 508 611 674 713 735 87.7 % 2013 180 388 545 656 717 754 82.6 % 2014 187 406 565 668 741 76.7 % 2015 176 406 569 692 67.2 % 2016 184 411 571 52.1 % 2017 196 414 34.5 % 2018 207 16.5 % Total $ 6,369 Unpaid losses and LAE — years 2009 through 2018 3,407 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) 477 Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 3,884 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 19.1 % 23.2 % 16.2 % 11.1 % 7.0 % 4.3 % 2.6 % 1.9 % 1.3 % 1.0 % Cumulative 19.1 % 42.3 % 58.5 % 69.6 % 76.6 % 80.9 % 83.5 % 85.4 % 86.7 % 87.7 % (a) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Specialty financial (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 192 $ 192 $ 186 $ 184 $ 188 $ 186 $ 187 $ 186 $ 185 $ 186 $ 1 27,431 2010 138 145 132 132 135 133 130 127 126 1 21,922 2011 138 157 155 153 147 144 143 139 6 16,368 2012 163 163 151 139 137 135 132 6 21,064 2013 140 145 137 131 127 126 9 28,449 2014 146 157 156 153 147 9 29,411 2015 156 160 158 153 16 37,483 2016 179 184 187 24 44,820 2017 212 215 34 46,921 2018 212 79 36,606 Total $ 1,623 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (a) 2009 $ 112 $ 145 $ 157 $ 166 $ 171 $ 181 $ 185 $ 186 $ 186 $ 185 99.5 % 2010 61 93 104 122 132 130 128 126 126 100.0 % 2011 58 111 115 123 130 131 131 132 95.0 % 2012 71 104 109 117 121 126 128 97.0 % 2013 70 100 107 113 117 117 92.9 % 2014 62 109 125 128 137 93.2 % 2015 72 110 129 133 86.9 % 2016 88 141 158 84.5 % 2017 120 169 78.6 % 2018 112 52.8 % Total $ 1,397 Unpaid losses and LAE — years 2009 through 2018 226 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) (1 ) Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 225 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 50.5 % 26.4 % 7.5 % 5.8 % 4.7 % 1.7 % 0.5 % (0.1 %) — % (0.5 %) Cumulative 50.5 % 76.9 % 84.4 % 90.2 % 94.9 % 96.6 % 97.1 % 97.0 % 97.0 % 96.5 % (a) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Other specialty (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims (a) Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 41 $ 41 $ 41 $ 40 $ 37 $ 37 $ 36 $ 38 $ 33 $ 32 $ 6 — 2010 36 39 40 39 40 40 40 40 40 3 — 2011 39 43 42 43 43 44 44 43 3 — 2012 42 40 39 40 41 39 39 6 — 2013 46 47 46 47 50 53 2 — 2014 58 57 59 59 60 13 — 2015 59 60 63 66 8 — 2016 61 61 65 21 — 2017 63 65 36 — 2018 86 62 — Total $ 549 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (b) 2009 $ 8 $ 12 $ 15 $ 19 $ 22 $ 22 $ 24 $ 26 $ 25 $ 27 84.4 % 2010 8 14 21 24 27 33 35 36 37 92.5 % 2011 12 20 25 28 34 36 37 38 88.4 % 2012 8 17 21 25 28 30 30 76.9 % 2013 7 16 22 34 37 44 83.0 % 2014 13 21 30 36 43 71.7 % 2015 10 26 31 50 75.8 % 2016 9 19 31 47.7 % 2017 10 19 29.2 % 2018 12 14.0 % Total $ 331 Unpaid losses and LAE — years 2009 through 2018 218 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) 62 Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 280 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 18.7 % 17.0 % 12.6 % 14.1 % 9.3 % 7.6 % 3.4 % 3.7 % (0.3 %) 6.3 % Cumulative 18.7 % 35.7 % 48.3 % 62.4 % 71.7 % 79.3 % 82.7 % 86.4 % 86.1 % 92.4 % (a) The amounts shown in Other specialty represent business assumed by AFG’s internal reinsurance program from the operations that make up AFG’s other Specialty property and casualty insurance sub-segments. Accordingly, the liability for incurred claims and allocated LAE represents additional reserves held on claims counted in the tables provided for the other sub-segments (above). (b) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ). Total Specialty Group (Dollars in Millions) Incurred Claims and Allocated LAE, Net of Reinsurance As of December 31, 2018 For the Years Ended (2009–2017 is Supplementary Information and Unaudited) Total IBNR Plus Expected Development on Reported Claims Cumulative Number of Reported Claims Accident Year 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2009 $ 1,624 $ 1,607 $ 1,596 $ 1,566 $ 1,552 $ 1,545 $ 1,543 $ 1,539 $ 1,529 $ 1,519 $ 43 222,664 2010 1,724 1,710 1,705 1,690 1,710 1,698 1,698 1,690 1,676 54 216,568 2011 1,840 1,848 1,849 1,871 1,861 1,866 1,859 1,843 67 209,098 2012 1,970 1,952 1,946 1,947 1,955 1,941 1,906 89 218,585 2013 2,036 2,011 2,000 1,996 2,000 1,982 128 221,362 2014 2,083 2,050 2,040 2,038 2,004 186 220,164 2015 2,114 2,047 2,041 2,038 245 227,435 2016 2,117 2,083 2,082 432 220,481 2017 2,375 2,348 737 240,542 2018 2,507 1,123 205,419 Total $ 19,905 Cumulative Paid Claims and Allocated LAE, Net of Reinsurance Accident Year For the Years Ended (2009–2017 is Supplementary Information and Unaudited) 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 % (a) 2009 $ 509 $ 871 $ 1,079 $ 1,216 $ 1,308 $ 1,370 $ 1,404 $ 1,424 $ 1,435 $ 1,445 95.1 % 2010 576 1,005 1,220 1,387 1,485 1,536 1,562 1,580 1,595 95.2 % 2011 609 1,181 1,389 1,534 1,629 1,682 1,711 1,734 94.1 % 2012 824 1,214 1,418 1,579 1,675 1,735 1,785 93.7 % 2013 697 1,214 1,443 1,617 1,714 1,774 89.5 % 2014 594 1,174 1,422 1,588 1,705 85.1 % 2015 619 1,129 1,404 1,592 78.1 % 2016 577 1,099 1,350 64.8 % 2017 709 1,250 53.2 % 2018 730 29.1 % Total $ 14,960 Unpaid losses and LAE — years 2009 through 2018 4,945 Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE) 561 Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE) $ 5,506 Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Annual 32.6 % 25.5 % 12.2 % 8.8 % 5.5 % 3.2 % 2.0 % 1.2 % 0.8 % 0.7 % Cumulative 32.6 % 58.1 % 70.3 % 79.1 % 84.6 % 87.8 % 89.8 % 91.0 % 91.8 % 92.5 % (a) Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018 ).
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 2018 2017 2016 2018 2017 Property and casualty companies $ 546 $ 484 $ 461 $ 2,867 $ 2,729 Life insurance companies 802 286 167 2,701 2,132
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. 2018 2017 2016 Direct premiums written $ 6,626 $ 6,310 $ 5,858 Reinsurance assumed 214 192 123 Reinsurance ceded (1,817 ) (1,751 ) (1,595 ) Net written premiums $ 5,023 $ 4,751 $ 4,386 Direct premiums earned $ 6,472 $ 6,112 $ 5,745 Reinsurance assumed 204 157 118 Reinsurance ceded (1,811 ) (1,690 ) (1,535 ) Net earned premiums $ 4,865 $ 4,579 $ 4,328 Reinsurance recoveries $ 1,249 $ 1,379 $ 810
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 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): 2018 2017 Expected death and annuitization $ 229 $ 228 Guaranteed withdrawal benefits 472 358 Accrued persistency and premium bonuses 1 3

Accounting Policies - Narrative

Accounting Policies - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Significant Accounting Policies [Line Items]
Cumulative effect of accounting change	$ 4		$ 4
Stranded amount reclassified from AOCI to retained earnings			$ 0
Weighted average common shares adjustment related to stock-based compensation		1,600,000	2,000,000	1,600,000
Anti-dilutive potential common shares related to stock-based compensation plans		0	0	400,000
Maturities of short term investments		3 months
Accounting Standards Update 2016-02 | Maximum
Significant Accounting Policies [Line Items]
Cumulative effect of accounting change		0.50%
Equity securities
Significant Accounting Policies [Line Items]
Available-for-sale securities, Equity securities	1,600		$ 1,600
Equity securities, trading at fair value	62		$ 62
Equity securities | Accounting Standards Update 2016-01
Significant Accounting Policies [Line Items]
Cumulative effect of accounting change					$ (221)
Tax Cuts and Jobs Act of 2017 | Accounting Standards Update 2018-02
Significant Accounting Policies [Line Items]
Stranded amount reclassified from AOCI to retained earnings	$ 145
Limited partnerships and similar investments | Accounting Standards Update 2016-01
Significant Accounting Policies [Line Items]
Cumulative effect of accounting change					$ (4)
Equity securities still owned | Equity securities | Accounting Standards Update 2016-01
Significant Accounting Policies [Line Items]
Net holding gains (losses) on equity securities		$ (257)

Acquisitions and Sale of Busi_3

Acquisitions and Sale of Businesses - Narrative on acquisitions of subsidiaries (Details) - USD ($) $ / shares in Units, $ in Millions	Nov. 10, 2016	Nov. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisitions [Line Items]
Payments to acquire subsidiaries						$ 36	$ 0	$ 0
Goodwill acquired during period			$ 8			8
Payments to acquire additional interest in subsidiaries						0	0	315
Income tax expense (benefit)						122	247	119
National Interstate
Business Acquisitions [Line Items]
Percentage ownership of National Interstate by noncontrolling owners prior to acquisition	49.00%
Payments to acquire additional interest in subsidiaries	$ 315
Acquisition price per share (USD per share)	$ 32
Cash dividend paid (USD per share)	$ 0.50
Payment of special cash dividends	$ 5
Payments for acquisition related costs					$ 10
ABA Insurance Services
Business Acquisitions [Line Items]
Payments to acquire subsidiaries		$ 30
Contingent consideration			$ 3			$ 3
Contingent consideration term						4 years
Finite-lived intangible assets acquired		25
Finite-lived intangible asset useful life						9 years
Goodwill acquired during period		$ 8
AFG
Business Acquisitions [Line Items]
Income tax expense (benefit)				$ (56)		$ 122	$ 247	$ 119
AFG | National Interstate
Business Acquisitions [Line Items]
Reduction to capital surplus	$ (137)
Income tax expense (benefit)					$ (66)

Acquisitions and Sale of Busi_4

Acquisitions and Sale of Businesses - Narrative on sale of businesses (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Sale of Businesses
Sale of redeemable noncontrolling interests				$ (3)
Income tax expense (benefit)			$ 122	247	$ 119
Neon Capital Limited
Sale of Businesses
Sale of redeemable noncontrolling interests	$ (3)
Income tax expense (benefit)	(56)	$ (111)			(48)
AFG
Sale of Businesses
Income tax expense (benefit)	$ (56)		$ 122	$ 247	$ 119

Acquisitions and Sale of Busi_5

Acquisitions and Sale of Businesses - Allocation of the purchase price of subsidiary (Details) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
		Nov. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisitions [Line Items]
Total purchase price			$ 36	$ 0	$ 0
Goodwill			$ 207	$ 199	$ 199	$ 199
ABA Insurance Services
Business Acquisitions [Line Items]
Total purchase price		$ 30
Tangible assets acquired		28
Liabilities acquired		26
Net tangible assets acquire, at fair value		2
Excess purchase price over net tangible assets acquired		28
Intangible assets acquired	[1]	25
Deferred tax on intangible assets acquired	[1]	(5)
Goodwill		$ 8
[1]	Included in Other assets in AFG’s Balance Sheet.

Segments of Operations - Narrat

Segments of Operations - Narrative (Details) $ in Millions	3 Months Ended				12 Months Ended
	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2018USD ($)segment	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Segment Reporting Information [Line Items]
Number of segments | segment					3
Revenue derived from sales of property and casualty insurance outside of the United States					7.00%	5.00%	4.00%
Property and casualty insurance | Real estate investment
Segment Reporting Information [Line Items]
Pretax income from the sale of real estate properties included in other income				$ 13			$ 32
Property and casualty insurance | Other lines
Segment Reporting Information [Line Items]
Special charges to increase asbestos and environmental reserves	$ 18		$ 89		$ 18	$ 89	36
Favorable reserve development related to certain lines of business within subsidiaries in connection with a reinsurance to close agreement						18
Special charges related to the exit of certain lines of business within subsidiaries							65
Other
Segment Reporting Information [Line Items]
Special charges to increase asbestos and environmental reserves					$ 9	24	$ 5
Make-whole premium, settlement of interest rate swap and write off of deferred debt issuance cost included in the loss on the retirement of debt		$ 40				$ 51

Segments of Operations - Assets

Segments of Operations - Assets by segment and sub-segment (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total assets		$ 63,456	$ 60,658	$ 55,072
Property and casualty insurance
Segment Reporting Information [Line Items]
Total assets	[1]	17,681	17,171	15,574
Annuity
Segment Reporting Information [Line Items]
Total assets		39,952	37,179	33,409
Other
Segment Reporting Information [Line Items]
Total assets		$ 5,823	$ 6,308	$ 6,089
[1]	Not allocable to sub-segments.

Segments of Operations - Revenu

Segments of Operations - Revenues by segment and sub-segment (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total premiums earned										$ 4,865	$ 4,579	$ 4,328
Net investment income										2,094	1,831	1,696
Other income										199	206	224
Revenues before realized gains (losses)										7,416	6,860	6,477
Realized gains (losses) on securities										(266)	5	19
Realized gains on subsidiaries										0	0	2
Total revenues		$ 1,690	$ 2,008	$ 1,833	$ 1,619	$ 1,808	$ 1,835	$ 1,646	$ 1,576	7,150	6,865	6,498
Property and casualty insurance
Segment Reporting Information [Line Items]
Total premiums earned										4,865	4,579	4,328
Net investment income										438	362	350
Other income	[1]									10	28	51
Revenues before realized gains (losses)										5,313	4,969	4,729
Annuity
Segment Reporting Information [Line Items]
Net investment income										1,638	1,458	1,356
Other income										107	103	103
Revenues before realized gains (losses)										1,745	1,561	1,459
Other
Segment Reporting Information [Line Items]
Revenues before realized gains (losses)										358	330	289
Property and transportation | Property and casualty insurance
Segment Reporting Information [Line Items]
Total premiums earned										1,729	1,711	1,662
Specialty casualty | Property and casualty insurance
Segment Reporting Information [Line Items]
Total premiums earned										2,403	2,186	2,006
Specialty financial | Property and casualty insurance
Segment Reporting Information [Line Items]
Total premiums earned										598	576	557
Other specialty | Property and casualty insurance
Segment Reporting Information [Line Items]
Total premiums earned										$ 135	$ 106	$ 103
[1]	Includes income of $32 million (before noncontrolling interest) from the sale of an apartment property in 2016.

Segments of Operations - Earnin

Segments of Operations - Earnings before income taxes by segment and sub-segment (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes		$ 905	$ 719	$ 766
Realized gains (losses) on securities		(266)	5	19
Realized gains on subsidiaries		0	0	2
Earnings before income taxes		639	724	787
Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting		302	242	236
Investment and other income, net	[1]	407	349	341
Earnings before realized gains (losses) and income taxes		709	591	577
Annuity
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes		361	380	368
Other
Segment Reporting Information [Line Items]
Earnings before realized gains (losses) and income taxes	[2]	(165)	(252)	(179)
Property and transportation | Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting		120	154	166
Specialty casualty | Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting		141	104	78
Specialty financial | Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting		66	61	84
Other specialty | Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting		(5)	(2)	9
Other lines | Property and casualty insurance
Segment Reporting Information [Line Items]
Property and casualty insurance underwriting	[3]	$ (20)	$ (75)	$ (101)
[1]	Includes income of $32 million (before noncontrolling interest) from the sale of an apartment property in 2016.
[2]	Primarily holding company interest and expenses, including losses on retirement of debt of $51 million in 2017 and special charges to increase A&E reserves related to AFG’s former railroad and manufacturing operations ($9 million in 2018, $24 million in 2017 and $5 million in 2016).
[3]	Includes special charges to increase asbestos and environmental (“A&E”) reserves of $18 million, $89 million and $36 million in 2018, 2017 and 2016, respectively. Also includes $18 million in favorable development related to the Neon exited lines recorded in connection with a reinsurance to close transaction in 2017 and a charge of $65 million related to Neon exited lines in 2016.

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)basispointsecurityprofessional	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Fair Value Measurements (Textual) [Abstract]
AFG's internal investment professionals | professional		25
Level 3 assets as a percentage of total assets measured at fair value		7.00%
Percentage of level 3 assets that were priced using non-binding broker quotes		69.00%
Level 3 assets that were priced using non-binding broker quotes		$ 2,410
Percent of spreads between 400 and 700 basis points		80.00%
Fair value of equity securities transferred into level 3		$ 270	$ 289	$ 139
Life contingent annuities		232	206
Fixed-indexed and variable-indexed annuities (embedded derivative)
Fair Value Measurements (Textual) [Abstract]
Fair value of derivatives in annuity benefits accumulated measured using a discounted cash flow approach		$ 2,720
Fixed-indexed and variable-indexed annuities (embedded derivative) | Minimum
Fair Value Measurements (Textual) [Abstract]
Unobservable input surrenders used in Level 3 fair value determination		3.00%
Fixed-indexed and variable-indexed annuities (embedded derivative) | Maximum
Fair Value Measurements (Textual) [Abstract]
Unobservable input surrenders used in Level 3 fair value determination		23.00%
Fixed-indexed annuities (embedded derivative), majority of future years | Minimum
Fair Value Measurements (Textual) [Abstract]
Unobservable input surrenders used in Level 3 fair value determination		7.00%
Fixed-indexed annuities (embedded derivative), majority of future years | Maximum
Fair Value Measurements (Textual) [Abstract]
Unobservable input surrenders used in Level 3 fair value determination		11.00%
Not Designated as Hedging Instrument | Annuity benefits | Fixed-indexed and variable-indexed annuities (embedded derivative)
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		$ (44)	(25)	(17)
Level 3
Fair Value Measurements (Textual) [Abstract]
Internally developed level 3 assets		1,050
Fixed maturities
Fair Value Measurements (Textual) [Abstract]
Fair value of equity securities transferred into level 3		240	289	124
Equity securities
Fair Value Measurements (Textual) [Abstract]
Fair value of equity securities transferred into level 3	$ 29	30	$ 0	$ 15
Third party pricing model | Fixed maturities | Level 3
Fair Value Measurements (Textual) [Abstract]
Internally developed level 3 assets		$ 590
Securities priced using third-party model | security		100
Basis points credit spread applied by management using third party model | basispoint		585
Third party pricing model | Fixed maturities | Level 3 | Minimum
Fair Value Measurements (Textual) [Abstract]
Basis points credit spread applied by management using third party model | basispoint		131
Third party pricing model | Fixed maturities | Level 3 | Maximum
Fair Value Measurements (Textual) [Abstract]
Basis points credit spread applied by management using third party model | basispoint		2,966
Maximum | Third party pricing model | Fixed maturities | Level 3
Fair Value Measurements (Textual) [Abstract]
Basis points credit spread applied by management using third party model | basispoint		700
Minimum | Third party pricing model | Fixed maturities | Level 3
Fair Value Measurements (Textual) [Abstract]
Basis points credit spread applied by management using third party model | basispoint		400

Fair Value Measurements - Asset

Fair Value Measurements - Assets and liabilities measured and carried at fair value in the financial statements (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Assets:
Available for sale (AFS) fixed maturities		$ 41,997	$ 38,379
Trading fixed maturities		105	348
Equity securities, at fair value		1,814	1,662
Assets of managed investment entities (MIE)		4,700	4,902
Variable annuity assets (separate accounts)	[1]	557	644
Derivatives including equity index call options and other assets		184	701
Total assets accounted for at fair value		49,373	46,636
Liabilities:
Liabilities of managed investment entities		4,512	4,687
Total liabilities accounted for at fair value		7,281	7,264
Derivatives in annuity benefits accumulated
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		2,720	2,542
Other liabilities — derivatives
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		49	35
Fixed maturities
Assets:
Available for sale (AFS) fixed maturities		41,997	38,379
Trading fixed maturities		105	348
U.S. Government and government agencies
Assets:
Available for sale (AFS) fixed maturities		233	242
States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities		6,939	7,123
Foreign government
Assets:
Available for sale (AFS) fixed maturities		142	127
Residential MBS
Assets:
Available for sale (AFS) fixed maturities		2,744	3,227
Commercial MBS
Assets:
Available for sale (AFS) fixed maturities		920	962
Asset-backed securities
Assets:
Available for sale (AFS) fixed maturities		9,811	7,962
Corporate and other
Assets:
Available for sale (AFS) fixed maturities		21,208	18,736
Equity securities
Assets:
Equity securities, at fair value		1,814	1,662
Other assets — derivatives
Assets:
Derivatives including equity index call options and other assets		16	0
Level 1
Assets:
Assets of managed investment entities (MIE)		203	307
Variable annuity assets (separate accounts)	[1]	0	0
Total assets accounted for at fair value		1,791	1,914
Liabilities:
Liabilities of managed investment entities		195	293
Total liabilities accounted for at fair value		195	293
Level 1 | Derivatives in annuity benefits accumulated
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		0	0
Level 1 | Other liabilities — derivatives
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		0	0
Level 1 | Fixed maturities
Assets:
Available for sale (AFS) fixed maturities		169	152
Trading fixed maturities		9	44
Level 1 | U.S. Government and government agencies
Assets:
Available for sale (AFS) fixed maturities		141	122
Level 1 | States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities		0	0
Level 1 | Foreign government
Assets:
Available for sale (AFS) fixed maturities		0	0
Level 1 | Residential MBS
Assets:
Available for sale (AFS) fixed maturities		0	0
Level 1 | Commercial MBS
Assets:
Available for sale (AFS) fixed maturities		0	0
Level 1 | Asset-backed securities
Assets:
Available for sale (AFS) fixed maturities		0	0
Level 1 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities		28	30
Level 1 | Equity securities
Assets:
Equity securities, at fair value		1,410	1,411
Level 1 | Other assets — derivatives
Assets:
Derivatives including equity index call options and other assets		0	0
Level 2
Assets:
Assets of managed investment entities (MIE)		4,476	4,572
Variable annuity assets (separate accounts)	[1]	557	644
Total assets accounted for at fair value		44,061	42,432
Liabilities:
Liabilities of managed investment entities		4,297	4,372
Total liabilities accounted for at fair value		4,346	4,407
Level 2 | Derivatives in annuity benefits accumulated
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		0	0
Level 2 | Other liabilities — derivatives
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		49	35
Level 2 | Fixed maturities
Assets:
Available for sale (AFS) fixed maturities		38,664	36,125
Trading fixed maturities		96	304
Level 2 | U.S. Government and government agencies
Assets:
Available for sale (AFS) fixed maturities		83	112
Level 2 | States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities		6,880	6,975
Level 2 | Foreign government
Assets:
Available for sale (AFS) fixed maturities		142	127
Level 2 | Residential MBS
Assets:
Available for sale (AFS) fixed maturities		2,547	3,105
Level 2 | Commercial MBS
Assets:
Available for sale (AFS) fixed maturities		864	926
Level 2 | Asset-backed securities
Assets:
Available for sale (AFS) fixed maturities		8,964	7,218
Level 2 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities		19,184	17,662
Level 2 | Equity securities
Assets:
Equity securities, at fair value		68	86
Level 2 | Other assets — derivatives
Assets:
Derivatives including equity index call options and other assets		16	0
Level 3
Assets:
Assets of managed investment entities (MIE)		21	23
Variable annuity assets (separate accounts)	[1]	0	0
Total assets accounted for at fair value		3,521	2,290
Liabilities:
Liabilities of managed investment entities		20	22
Total liabilities accounted for at fair value		2,740	2,564
Level 3 | Derivatives in annuity benefits accumulated
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		2,720	2,542
Level 3 | Other liabilities — derivatives
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		0	0
Level 3 | Fixed maturities
Assets:
Available for sale (AFS) fixed maturities		3,164	2,102
Trading fixed maturities		0	0
Level 3 | U.S. Government and government agencies
Assets:
Available for sale (AFS) fixed maturities		9	8
Level 3 | States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities		59	148
Level 3 | Foreign government
Assets:
Available for sale (AFS) fixed maturities		0	0
Level 3 | Residential MBS
Assets:
Available for sale (AFS) fixed maturities		197	122
Level 3 | Commercial MBS
Assets:
Available for sale (AFS) fixed maturities		56	36
Level 3 | Asset-backed securities
Assets:
Available for sale (AFS) fixed maturities		847	744
Level 3 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities		1,996	1,044
Level 3 | Equity securities
Assets:
Equity securities, at fair value		336	165
Level 3 | Other assets — derivatives
Assets:
Derivatives including equity index call options and other assets		0	0
Equity index call options | Equity index call options
Assets:
Derivatives including equity index call options and other assets		184	701
Equity index call options | Level 1 | Equity index call options
Assets:
Derivatives including equity index call options and other assets		0	0
Equity index call options | Level 2 | Equity index call options
Assets:
Derivatives including equity index call options and other assets		184	701
Equity index call options | Level 3 | Equity index call options
Assets:
Derivatives including equity index call options and other assets		$ 0	$ 0
[1]	Variable annuity liabilities equal the fair value of variable annuity assets.

Fair Value Measurements - Trans

Fair Value Measurements - Transfers between Level 1 and Level 2 (Details) $ in Millions	Dec. 31, 2018USD ($)stock	Dec. 31, 2017USD ($)stock	Dec. 31, 2016USD ($)stock
Perpetual preferred stocks
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of stocks transferred from Level 2 to Level 1 | stock	2	4	6
Fair value of assets transferred from Level 2 to Level 1 | $	$ 5	$ 23	$ 35
Number of stocks transferred from Level 1 to Level 2 | stock	2	2	7
Fair value of assets transferred from Level 1 to Level 2 | $	$ 6	$ 11	$ 28
Common stocks
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of stocks transferred from Level 2 to Level 1 | stock	0	0	3
Fair value of assets transferred from Level 2 to Level 1 | $	$ 0	$ 0	$ 0
Number of stocks transferred from Level 1 to Level 2 | stock	0	1	2
Fair value of assets transferred from Level 1 to Level 2 | $	$ 0	$ 0	$ 0

Fair Value Measurements - Unobs

Fair Value Measurements - Unobservable inputs used in determining fair value of embedded derivatives (Details) - Embedded derivatives	12 Months Ended
	Dec. 31, 2018
Unobservable inputs used by management in determining fair value of embedded derivatives
Risk margin for uncertainty in cash flows	0.73%
Minimum
Unobservable inputs used by management in determining fair value of embedded derivatives
Fair Value Input Adjustment for Insurance Subsidiary’s Credit Risk	0.60%
Surrenders	3.00%
Partial surrenders	2.00%
Annuitizations	0.10%
Deaths	1.50%
Budgeted option costs	2.60%
Maximum
Unobservable inputs used by management in determining fair value of embedded derivatives
Fair Value Input Adjustment for Insurance Subsidiary’s Credit Risk	2.10%
Surrenders	23.00%
Partial surrenders	9.00%
Annuitizations	1.00%
Deaths	9.50%
Budgeted option costs	3.60%

Fair Value Measurements - Chang

Fair Value Measurements - Changes in balances of Level 3 financial assets carried at fair value (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	$ 2,290	$ 2,290	$ 1,762	$ 1,636
Total realized/unrealized gains (losses) included in Net earnings		(21)	(39)	(35)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)		(39)	17	21
Purchases and issuances		1,828	1,079	347
Sales and settlements		(482)	(437)	(217)
Transfer into Level 3		270	289	139
Transfer out of Level 3		(325)	(381)	(129)
Financial assets, Ending Balance		3,521	2,290	1,762
Fixed maturities
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	2,102	2,102	1,559	1,470
Total realized/unrealized gains (losses) included in Net earnings		(22)	(7)	(14)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)		(39)	7	(14)
Purchases and issuances		1,667	1,032	291
Sales and settlements		(476)	(421)	(189)
Transfer into Level 3		240	289	124
Transfer out of Level 3		(308)	(357)	(109)
Financial assets, Ending Balance		3,164	2,102	1,559
U.S. government agency
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	8	8	8	15
Total realized/unrealized gains (losses) included in Net earnings		0	0	(8)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)		0	0	1
Purchases and issuances		0	0	0
Sales and settlements		0	0	0
Transfer into Level 3		1	0	0
Transfer out of Level 3		0	0	0
Financial assets, Ending Balance		9	8	8
State and municipal
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	148	148	140	89
Total realized/unrealized gains (losses) included in Net earnings		0	0	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)		(2)	2	(4)
Purchases and issuances		0	0	57
Sales and settlements		(3)	(2)	(2)
Transfer into Level 3		0	10	0
Transfer out of Level 3		(84)	(2)	0
Financial assets, Ending Balance		59	148	140
Residential MBS
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	122	122	190	224
Total realized/unrealized gains (losses) included in Net earnings		(9)	(4)	(4)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)		(4)	2	(2)
Purchases and issuances		0	1	8
Sales and settlements		(21)	(40)	(28)
Transfer into Level 3		130	44	34
Transfer out of Level 3		(21)	(71)	(42)
Financial assets, Ending Balance		197	122	190
Commercial MBS
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	36	36	25	39
Total realized/unrealized gains (losses) included in Net earnings		0	2	(1)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)		0	0	0
Purchases and issuances		20	15	0
Sales and settlements		0	(10)	(7)
Transfer into Level 3		0	4	0
Transfer out of Level 3		0	0	(6)
Financial assets, Ending Balance		56	36	25
Asset-backed securities
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	744	744	484	470
Total realized/unrealized gains (losses) included in Net earnings		(3)	0	(1)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)		(15)	1	1
Purchases and issuances		426	410	50
Sales and settlements		(248)	(132)	(52)
Transfer into Level 3		82	202	60
Transfer out of Level 3		(139)	(221)	(44)
Financial assets, Ending Balance		847	744	484
Corporate and other
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	1,044	1,044	712	633
Total realized/unrealized gains (losses) included in Net earnings		(10)	(5)	0
Total realized/unrealized gains (losses) included in other comprehensive income (loss)		(18)	2	(10)
Purchases and issuances		1,221	606	176
Sales and settlements		(204)	(237)	(100)
Transfer into Level 3		27	29	30
Transfer out of Level 3		(64)	(63)	(17)
Financial assets, Ending Balance		1,996	1,044	712
Equity securities
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	165	165	174	140
Total realized/unrealized gains (losses) included in Net earnings		9	(21)	(12)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)		0	10	35
Purchases and issuances		155	38	44
Sales and settlements		(6)	(16)	(28)
Transfer into Level 3	29	30	0	15
Transfer out of Level 3		(17)	(20)	(20)
Financial assets, Ending Balance		336	165	174
Assets of MIE
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Financial assets, Beginning Balance	$ 23	23	29	26
Total realized/unrealized gains (losses) included in Net earnings		(8)	(11)	(9)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)		0	0	0
Purchases and issuances		6	9	12
Sales and settlements		0	0	0
Transfer into Level 3		0	0	0
Transfer out of Level 3		0	(4)	0
Financial assets, Ending Balance		$ 21	$ 23	$ 29

Fair Value Measurements - Cha_2

Fair Value Measurements - Changes in balances of Level 3 financial liabilities carried at fair value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial liabilities, Beginning Balance	$ (2,542)	[1]	$ (1,759)	[2]	$ (1,369)
Total realized/unrealized gains (losses) included in Net earnings	204		(589)		(211)
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0		0		0
Purchases and issuances	(545)		(300)		(277)
Sales and settlements	163		106		98
Transfer into Level 3	0		0		0
Transfer out of Level 3	0		0		0
Financial liabilities, Ending Balance	(2,720)	[3]	(2,542)	[1]	(1,759)	[2]
Embedded derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial liabilities, Beginning Balance	(2,542)		(1,759)		(1,369)
Total realized/unrealized gains (losses) included in Net earnings	204	[4]	(589)	[5]	(211)	[6]
Total realized/unrealized gains (losses) included in other comprehensive income (loss)	0		0		0
Purchases and issuances	(545)		(300)		(277)
Sales and settlements	163		106		98
Transfer into Level 3	0		0		0
Transfer out of Level 3	0		0		0
Financial liabilities, Ending Balance	$ (2,720)		$ (2,542)		$ (1,759)
[1]	As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets.
[2]	As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets.
[3]	As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets.
[4]	Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $44 million in 2018.
[5]	Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $25 million in 2017.
[6]	Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $17 million in 2016.

Fair Value Measurements - The c

Fair Value Measurements - The carrying value and fair value of financial instruments (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Financial assets:
Mortgage loans		$ 1,068	$ 1,125
Policy loans		174	184
Financial liabilities:
Long-term debt		1,302	1,301
Level 1
Financial assets:
Cash and cash equivalents		1,515	2,338
Mortgage loans		0	0
Policy loans		0	0
Total financial assets not accounted for at fair value		1,515	2,338
Financial liabilities:
Annuity benefits accumulated	[1]	0	0
Long-term debt		0	0
Total financial liabilities not accounted for at fair value		0	0
Level 2
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	[1]	0	0
Long-term debt		1,228	1,351
Total financial liabilities not accounted for at fair value		1,228	1,351
Level 3
Financial assets:
Cash and cash equivalents		0	0
Mortgage loans		1,056	1,119
Policy loans		174	184
Total financial assets not accounted for at fair value		1,230	1,303
Financial liabilities:
Annuity benefits accumulated	[1]	34,765	32,461
Long-term debt		3	3
Total financial liabilities not accounted for at fair value		34,768	32,464
Carrying Value
Financial assets:
Cash and cash equivalents		1,515	2,338
Mortgage loans		1,068	1,125
Policy loans		174	184
Total financial assets not accounted for at fair value		2,757	3,647
Financial liabilities:
Annuity benefits accumulated	[1]	36,384	33,110
Long-term debt		1,302	1,301
Total financial liabilities not accounted for at fair value		37,686	34,411
Fair Value
Financial assets:
Cash and cash equivalents		1,515	2,338
Mortgage loans		1,056	1,119
Policy loans		174	184
Total financial assets not accounted for at fair value		2,745	3,641
Financial liabilities:
Annuity benefits accumulated	[1]	34,765	32,461
Long-term debt		1,231	1,354
Total financial liabilities not accounted for at fair value		$ 35,996	$ 33,815
[1]	Excludes $232 million and $206 million of life contingent annuities in the payout phase at December 31, 2018 and 2017, respectively.

Investments - Narrative (Detail

Investments - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)security	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
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	92.00%
Percentage (based on fair value) of available for sale fixed maturities that are in an unrealized loss position and rated investment grade	96.00%
Other than temporary impairment charges	$ 19	$ 73	$ 116
Average life of ABS	4 years 6 months
Average life of MBS	4 years 6 months
Residential MBS
Investment [Line Items]
Non-credit related portion of other-than-temporary impairment charges taken for securities still owned	$ 140	158
Fixed maturities, Gross Unrealized, Losses	(9)	(6)
Other than temporary impairment charges	6	1	3
Securities with non-credit other-than-temporary impairment charges
Investment [Line Items]
Gross Unrealized, Gains	119	137
Gross Unrealized, Losses	(4)	(4)
Fixed maturities
Investment [Line Items]
Fixed maturities, Gross Unrealized, Losses	$ (603)	(82)
Number of available for sale securities in an unrealized loss position | security	2,324
Other than temporary impairment charges	$ 26	20	38
Available-for-sale Securities, Gross Realized Gains	22	43	55
Available-for-sale Securities, Gross Realized Losses	(14)	(20)	(10)
Fixed maturities excluding residential MBS
Investment [Line Items]
Other than temporary impairment charges	20	19	35
Other investments
Investment [Line Items]
Other than temporary impairment charges		4
Equity securities
Investment [Line Items]
Other than temporary impairment charges	0	64	93
Available-for-sale Securities, Gross Realized Gains		87	110
Available-for-sale Securities, Gross Realized Losses		(17)	(4)
Equity securities | Available-for-sale securities
Investment [Line Items]
Other than temporary impairment charges		$ 64	$ 93
Aircraft financing | Fixed maturities excluding residential MBS
Investment [Line Items]
Other than temporary impairment charges	$ 14

Investments - Available for sal

Investments - Available for sale fixed maturities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	$ 41,837	$ 37,038
Available for sale (AFS) fixed maturities	41,997	38,379
Total fixed maturities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	41,837	37,038
Fixed maturities, Available for sale, Gross Unrealized, Gains	763	1,423
Fixed maturities, Available for sale, Gross Unrealized, Losses	(603)	(82)
Fixed maturities, Available for sale, Net Unrealized, Gains (Losses)	160	1,341
Available for sale (AFS) fixed maturities	41,997	38,379
U.S. Government and government agencies
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	235	244
Fixed maturities, Available for sale, Gross Unrealized, Gains	1	1
Fixed maturities, Available for sale, Gross Unrealized, Losses	(3)	(3)
Fixed maturities, Available for sale, Net Unrealized, Gains (Losses)	(2)	(2)
Available for sale (AFS) fixed maturities	233	242
States, municipalities and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	6,825	6,887
Fixed maturities, Available for sale, Gross Unrealized, Gains	169	254
Fixed maturities, Available for sale, Gross Unrealized, Losses	(55)	(18)
Fixed maturities, Available for sale, Net Unrealized, Gains (Losses)	114	236
Available for sale (AFS) fixed maturities	6,939	7,123
Foreign government
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	140	124
Fixed maturities, Available for sale, Gross Unrealized, Gains	2	3
Fixed maturities, Available for sale, Gross Unrealized, Losses	0	0
Fixed maturities, Available for sale, Net Unrealized, Gains (Losses)	2	3
Available for sale (AFS) fixed maturities	142	127
Residential MBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	2,476	2,884
Fixed maturities, Available for sale, Gross Unrealized, Gains	277	349
Fixed maturities, Available for sale, Gross Unrealized, Losses	(9)	(6)
Fixed maturities, Available for sale, Net Unrealized, Gains (Losses)	268	343
Available for sale (AFS) fixed maturities	2,744	3,227
Commercial MBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	905	927
Fixed maturities, Available for sale, Gross Unrealized, Gains	17	36
Fixed maturities, Available for sale, Gross Unrealized, Losses	(2)	(1)
Fixed maturities, Available for sale, Net Unrealized, Gains (Losses)	15	35
Available for sale (AFS) fixed maturities	920	962
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	9,781	7,836
Fixed maturities, Available for sale, Gross Unrealized, Gains	130	142
Fixed maturities, Available for sale, Gross Unrealized, Losses	(100)	(16)
Fixed maturities, Available for sale, Net Unrealized, Gains (Losses)	30	126
Available for sale (AFS) fixed maturities	9,811	7,962
Corporate and other
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, Available for sale, Amortized Cost	21,475	18,136
Fixed maturities, Available for sale, Gross Unrealized, Gains	167	638
Fixed maturities, Available for sale, Gross Unrealized, Losses	(434)	(38)
Fixed maturities, Available for sale, Net Unrealized, Gains (Losses)	(267)	600
Available for sale (AFS) fixed maturities	$ 21,208	$ 18,736

Investments - Equity securities

Investments - Equity securities reported at fair value (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Debt and Equity Securities, FV-NI [Line Items]
Equity securities	$ 1,814	$ 1,662
Common stocks
Debt and Equity Securities, FV-NI [Line Items]
Equity securities, at cost	1,241
Equity securities	1,148
Equity securities, fair value in excess of cost	(93)
Perpetual preferred stocks
Debt and Equity Securities, FV-NI [Line Items]
Equity securities, at cost	705
Equity securities	666
Equity securities, fair value in excess of cost	(39)
Equity securities
Debt and Equity Securities, FV-NI [Line Items]
Equity securities, at cost	1,946
Equity securities	1,814
Equity securities, fair value in excess of cost	$ (132)

Investments - Gross unrealized

Investments - Gross unrealized losses on securities by investment category and length of time that have been in a continuous unrealized loss position (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Fixed maturities
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	$ (411)	$ (37)
Fair Value - Less than twelve months	$ 17,766	$ 4,295
Fair Value as % of Cost - Less than twelve months	98.00%	99.00%
Unrealized Loss - Twelve months or more	$ (192)	$ (45)
Fair Value - Twelve months or more	$ 3,902	$ 1,574
Fair Value as % of Cost - Twelve months or more	95.00%	97.00%
U.S. Government and government agencies
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	$ 0	$ 0
Fair Value - Less than twelve months	$ 41	$ 55
Fair Value as % of Cost - Less than twelve months	100.00%	100.00%
Unrealized Loss - Twelve months or more	$ (3)	$ (3)
Fair Value - Twelve months or more	$ 120	$ 123
Fair Value as % of Cost - Twelve months or more	98.00%	98.00%
States, municipalities and political subdivisions
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	$ (23)	$ (8)
Fair Value - Less than twelve months	$ 1,497	$ 825
Fair Value as % of Cost - Less than twelve months	98.00%	99.00%
Unrealized Loss - Twelve months or more	$ (32)	$ (10)
Fair Value - Twelve months or more	$ 902	$ 431
Fair Value as % of Cost - Twelve months or more	97.00%	98.00%
Foreign government
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	$ 0	$ 0
Fair Value - Less than twelve months	$ 18	$ 4
Fair Value as % of Cost - Less than twelve months	100.00%	100.00%
Unrealized Loss - Twelve months or more	$ 0	$ 0
Fair Value - Twelve months or more	$ 4	$ 0
Fair Value as % of Cost - Twelve months or more	100.00%	0.00%
Residential MBS
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	$ (4)	$ (1)
Fair Value - Less than twelve months	$ 279	$ 118
Fair Value as % of Cost - Less than twelve months	99.00%	99.00%
Unrealized Loss - Twelve months or more	$ (5)	$ (5)
Fair Value - Twelve months or more	$ 139	$ 118
Fair Value as % of Cost - Twelve months or more	97.00%	96.00%
Commercial MBS
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	$ (1)	$ (1)
Fair Value - Less than twelve months	$ 147	$ 67
Fair Value as % of Cost - Less than twelve months	99.00%	99.00%
Unrealized Loss - Twelve months or more	$ (1)	$ 0
Fair Value - Twelve months or more	$ 30	$ 0
Fair Value as % of Cost - Twelve months or more	97.00%	0.00%
Asset-backed securities
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	$ (77)	$ (7)
Fair Value - Less than twelve months	$ 5,406	$ 1,195
Fair Value as % of Cost - Less than twelve months	99.00%	99.00%
Unrealized Loss - Twelve months or more	$ (23)	$ (9)
Fair Value - Twelve months or more	$ 629	$ 299
Fair Value as % of Cost - Twelve months or more	96.00%	97.00%
Corporate and other
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	$ (306)	$ (20)
Fair Value - Less than twelve months	$ 10,378	$ 2,031
Fair Value as % of Cost - Less than twelve months	97.00%	99.00%
Unrealized Loss - Twelve months or more	$ (128)	$ (18)
Fair Value - Twelve months or more	$ 2,078	$ 603
Fair Value as % of Cost - Twelve months or more	94.00%	97.00%
Equity securities
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months		$ (22)
Fair Value - Less than twelve months		$ 158
Fair Value as % of Cost - Less than twelve months		88.00%
Unrealized Loss - Twelve months or more		$ (1)
Fair Value - Twelve months or more		$ 13
Fair Value as % of Cost - Twelve months or more		93.00%
Common stocks
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months		$ (22)
Fair Value - Less than twelve months		$ 117
Fair Value as % of Cost - Less than twelve months		84.00%
Unrealized Loss - Twelve months or more		$ 0
Fair Value - Twelve months or more		$ 0
Fair Value as % of Cost - Twelve months or more		0.00%
Perpetual preferred stocks
Available-for-sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months		$ 0
Fair Value - Less than twelve months		$ 41
Fair Value as % of Cost - Less than twelve months		100.00%
Unrealized Loss - Twelve months or more		$ (1)
Fair Value - Twelve months or more		$ 13
Fair Value as % of Cost - Twelve months or more		93.00%

Investments - Credit portion of

Investments - Credit portion of other-than-temporary impairments on fixed maturities for which the non-credit portion of an impairment has been recognized in OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance at January 1	$ 145	$ 153	$ 160
Additional credit impairments on:
Previously impaired securities	1	1	2
Securities without prior impairments	1	3	1
Reductions due to sales or redemptions	(5)	(12)	(10)
Balance at December 31	$ 142	$ 145	$ 153

Investments - Scheduled maturit

Investments - Scheduled maturities of available for sale fixed maturities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value Percent, Fiscal Year Maturity [Abstract]
Average life of ABS	4 years 6 months
Average life of MBS	4 years 6 months
Securities With Non-Credit Other Than Temporary Impairment Charges [Member]
Fair Value Percent, Fiscal Year Maturity [Abstract]
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	$ (4)	$ (4)
Fixed maturities
Amortized Cost Basis, Fiscal Year Maturity [Abstract]
One year or less	1,310
After one year through five years	8,521
After five years through ten years	14,235
After ten years	4,609
Fixed maturities amortized cost, Subtotal	28,675
ABS (average life of approximately 4.5 years)	9,781
MBS (average life of approximately 4.5 years)	3,381
Amortized Cost	41,837
Fair Value, Fiscal Year Maturity [Abstract]
One year or less	1,318
After one year through five years	8,554
After five years through ten years	14,044
After ten years	4,606
Fixed maturities fair value, Subtotal	28,522
ABS (average life of approximately 4.5 years)	9,811
MBS (average life of approximately 4.5 years)	3,664
Fair Value	$ 41,997
Fair Value Percent, Fiscal Year Maturity [Abstract]
One year or less	3.00%
After one year through five years	20.00%
After five years through ten years	34.00%
After ten years	11.00%
Fixed maturities fair value, Subtotal, Percent	68.00%
ABS (average life of approximately 4.5 years)	23.00%
MBS (average life of approximately 4.5 years)	9.00%
Fair value, Total, Percent	100.00%

Investments - Components of the

Investments - Components of the net unrealized gain on securities that is included in AOCI in the Balance Sheet (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Unrealized gain on:
Pretax		$ 105	$ 1,063
Deferred Tax		(22)	(223)
Net		83	840
Total investments
Unrealized gain on:
Pretax			1,620
Deferred Tax			(340)
Net			1,280
Total fixed maturities
Unrealized gain on:
Pretax		160	1,341
Deferred Tax		(34)	(282)
Net		126	1,059
Fixed maturities — annuity segment
Unrealized gain on:
Pretax	[1]	101	1,082
Deferred Tax	[1]	(21)	(227)
Net	[1]	80	855
Fixed maturities — all other
Unrealized gain on:
Pretax		59	259
Deferred Tax		(13)	(55)
Net		46	204
Equity securities
Unrealized gain on:
Pretax	[2]		279
Deferred Tax	[2]		(58)
Net	[2]		221
Deferred policy acquisition costs — annuity segment
Unrealized gain on:
Pretax		(42)	(433)
Deferred Tax		9	91
Net		(33)	(342)
Annuity benefits accumulated
Unrealized gain on:
Pretax		(14)	(137)
Deferred Tax		3	29
Net		(11)	(108)
Unearned revenue
Unrealized gain on:
Pretax		1	13
Deferred Tax		0	(3)
Net		$ 1	$ 10
[1]	Net unrealized gains on fixed maturity investments supporting AFG’s annuity benefits accumulated.
[2]	As discussed in Note A — “Accounting Policies — Investments,” effective January 1, 2018, all equity securities other than those accounted for under the equity method are carried at fair value through net earnings.

Investments - Schedule of sourc

Investments - Schedule of sources of net investment income (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net Investment Income [Line Items]
Gross investment income		$ 2,116	$ 1,852	$ 1,716
Investment expenses		(22)	(21)	(20)
Net investment income		2,094	1,831	1,696
Fixed maturities
Net Investment Income [Line Items]
Gross investment income		1,742	1,607	1,510
Equity in earnings of partnerships and similar investments
Net Investment Income [Line Items]
Gross investment income		161	64	44
Other
Net Investment Income [Line Items]
Gross investment income		112	102	81
Investment income | Equity securities
Net Investment Income [Line Items]
Gross investment income		79	73	77
Accounting Standards Update 2016-01 | Equity securities
Net Investment Income [Line Items]
Gross investment income	[1]	$ 22	$ 6	$ 4
[1]	As discussed in Note A — “Accounting Policies — Investments,” AFG adopted guidance in January 2018 that requires all equity securities other than those accounted for under the equity method to be reported at fair value with holding gains and losses recognized in net earnings. Although the change in the fair value of the majority of AFG’s equity securities is recorded in realized gains (losses) on securities, AFG records holding gains and losses in net investment income on equity securities classified as “trading” under the previous guidance and on a small portfolio of limited partnership and similar investments that do not qualify for the equity method of accounting.

Investments - Realized gains (l

Investments - Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		$ (247)	$ 78	$ 135
Realized - impairments		(19)	(73)	(116)
Total realized gains (losses) on securities		(266)	5	19
Net of tax
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		(195)	51	85
Realized - impairments		(15)	(48)	(72)
Total realized gains (losses) on securities		(210)	3	13
Change in unrealized		(536)	436	72
Total pretax
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		(247)	78	135
Realized - impairments		(19)	(73)	(116)
Total realized gains (losses) on securities		(266)	5	19
Change in unrealized		(679)	441	105
Fixed maturities
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		6	17	36
Realized - impairments		(26)	(20)	(38)
Total realized gains (losses) on securities		(20)	(3)	(2)
Change in unrealized		(1,181)	532	90
Equity securities
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		(265)	70	106
Realized - impairments		0	(64)	(93)
Total realized gains (losses) on securities		(265)	6	13
Change in unrealized		0	128	67
Mortgage loans and other investments
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		1	(6)
Realized - impairments		0	(4)
Total realized gains (losses) on securities		1	(10)
Change in unrealized		0	0
Other, Including DPAC and reserves on annuities and long-term care
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments	[1]	11	(3)	(7)
Realized - impairments	[1]	7	15	15
Total realized gains (losses) on securities	[1]	18	12	8
Change in unrealized	[1]	502	(219)	(52)
Total tax effects
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		52	(27)	(48)
Realized - impairments		4	25	41
Total realized gains (losses) on securities		56	(2)	(7)
Change in unrealized		143	(5)	(37)
Effects Of Tax Cuts And Jobs Act Of 2017
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		0	0
Realized - impairments		0	0
Total realized gains (losses) on securities		0	0
Change in unrealized		0	149
Other tax effects
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments		52	(27)
Realized - impairments		4	25
Total realized gains (losses) on securities		56	(2)
Change in unrealized		$ 143	$ (154)
Noncontrolling interests
Realized gains (losses) and changes in unrealized appreciation (depreciation) related to fixed maturity and equity security investments
Realized before impairments				(2)
Realized - impairments				3
Total realized gains (losses) on securities				1
Change in unrealized				$ 4
[1]	Primarily adjustments to deferred policy acquisition costs and reserves related to the annuity business.

Investments - Holding gains (lo

Investments - Holding gains (losses) on equity securities still held (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Holding Gains (Losses) on Equity Securities Still Held [Line Items]
Realized gains (losses) on securities		$ (266)	$ 5	$ 19
Gross investment income		2,116	1,852	1,716
Equity securities
Holding Gains (Losses) on Equity Securities Still Held [Line Items]
Realized gains (losses) on securities		(265)	$ 6	$ 13
Accounting Standards Update 2016-01 | Equity securities still owned | Equity securities
Holding Gains (Losses) on Equity Securities Still Held [Line Items]
Net holding gains (losses) on equity securities		(257)
Accounting Standards Update 2016-01 | Realized gains (losses) on securities | Equity securities still owned | Equity securities
Holding Gains (Losses) on Equity Securities Still Held [Line Items]
Realized gains (losses) on securities		(279)
Net holding gains (losses) on equity securities	$ (228)	(279)
Accounting Standards Update 2016-01 | Investment income | Equity securities still owned | Equity securities
Holding Gains (Losses) on Equity Securities Still Held [Line Items]
Gross investment income		$ 22

Investments - Gross realized ga

Investments - Gross realized gains and losses on available for sale fixed maturity security investment transactions (Details) - Fixed maturities - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Gross realized gains and losses on the sale of available for sale fixed maturity security investments
Gross gains	$ 22	$ 43	$ 55
Gross losses	$ (14)	$ (20)	$ (10)

Derivatives - Narrative (Detail

Derivatives - Narrative (Details)	12 Months Ended
	Dec. 31, 2018USD ($)swap	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Carrying value of collateral received to support purchased call options	$ 103,000,000	$ 389,000,000
Not Designated as Hedging Instrument | Fixed-indexed and variable-indexed annuities (embedded derivative) | Annuity benefits
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	(44,000,000)	(25,000,000)	$ (17,000,000)
Designated as Hedging Instrument | Interest rate swaps | Cash Flow Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivative instrument outstanding	$ 2,350,000,000	1,580,000,000
Designated as Hedging Instrument | Interest rate swaps | Cash Flow Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Number of interest rate swaps designated and qualifying as a cash flow hedges | swap	16
Number of interest rate swaps entered into during the period | swap	6
Gain (loss) reclassified from AOCI into net investment income	$ (3,000,000)	6,000,000	7,000,000
Gain (loss) on cash flow hedge ineffectiveness recorded in Net Earnings	0	0	$ 0
Collateral receivable supporting interest rate swaps	135,000,000	70,000,000
Designated as Hedging Instrument | Interest rate swaps | Cash Flow Hedges | Other assets
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives, at fair value	16,000,000
Designated as Hedging Instrument | Interest rate swaps | Cash Flow Hedges | Other assets | Maximum
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives, at fair value		1,000,000
Designated as Hedging Instrument | Interest rate swaps | Cash Flow Hedges | Other liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives, at fair value	(46,000,000)	$ (31,000,000)
Designated as Hedging Instrument | Interest rate swaps | Cash Flow Hedges | New interest rate swaps entered into during the period
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of derivative instrument outstanding	$ 911,000,000

Derivatives - Derivatives that

Derivatives - Derivatives that do not qualify for hedge accounting under GAAP included in the Balance Sheet at fair value (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivatives included in AFG' s Balance Sheet at fair value
Derivative asset, at fair value	$ 293	$ 810
Derivative liability, at fair value	2,723	2,546
MBS with embedded derivatives | Fixed maturities
Derivatives included in AFG' s Balance Sheet at fair value
Derivative asset, at fair value	109	105
Public company warrants | Equity securities
Derivatives included in AFG' s Balance Sheet at fair value
Derivative asset, at fair value	0	4
Fixed-indexed and variable-indexed annuities (embedded derivative) | Annuity benefits accumulated
Derivatives included in AFG' s Balance Sheet at fair value
Derivative liability, at fair value	2,720	2,542
Equity index call options | Equity index call options
Derivatives included in AFG' s Balance Sheet at fair value
Derivative asset, at fair value	184	701
Equity index put options | Other liabilities
Derivatives included in AFG' s Balance Sheet at fair value
Derivative liability, at fair value	1	0
Reinsurance contract (embedded derivative) | Other liabilities
Derivatives included in AFG' s Balance Sheet at fair value
Derivative liability, at fair value	$ 2	$ 4

Derivatives - Gain (loss) inclu

Derivatives - Gain (loss) included in the Statement of Earnings for changes in the fair value of derivatives that do not qualify for hedge accounting (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		$ (103)	$ (103)	$ (80)
MBS with embedded derivatives | Realized gains (losses) on securities
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		(7)	(6)	(9)
Public company warrants | Realized gains (losses) on securities
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		(3)	0	0
Fixed-indexed and variable-indexed annuities (embedded derivative) | Annuity benefits
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	[1]	204	(589)	(211)
Equity index call options | Annuity benefits
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		(298)	494	141
Equity index put options | Annuity benefits
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		(1)	0	0
Reinsurance contract (embedded derivative) | Net investment income
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		$ 2	$ (2)	$ (1)
[1]	The change in fair value of the embedded derivative includes losses related to unlocking of actuarial assumptions of $44 million in 2018, $25 million in 2017 and $17 million in 2016.

Deferred Policy Acquisition C_3

Deferred Policy Acquisition Costs - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Deferred Policy Acquisition Costs Disclosures [Abstract]
Accumulated amortization of present value of future profits	$ 148	$ 141
Approximate annual rate of decrease in present value of future profits during next five years	12.50%

Deferred Policy Acquisition C_4

Deferred Policy Acquisition Costs - Progression of deferred policy acquisition costs (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
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		$ 1,216	$ 1,239	$ 1,184
Deferred policy acquisition costs and present value of future profits, additions		940	817	774
Deferred policy acquisition costs and present value of future profits, periodic amortization		(908)	(744)	(722)
Deferred policy acquisition costs and present value of future profits, annuity unlocking		29	41	29
Deferred policy acquisition costs and present value of future profits, change included in realized gains		15	10	8
Deferred policy acquisition costs and present value of future profits, foreign currency translation		(2)	0	(3)
Deferred policy acquisition costs and present value of future profits, other			10
Deferred policy acquisition costs and present value of future profits, change in unrealized		392	(157)	(31)
Deferred policy acquisition costs and present value of future profits, ending balance		1,682	1,216	1,239
Property and casualty insurance
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs, beginning balance		270	238	226
Deferred policy acquisition costs, additions		675	588	535
Deferred policy acquisition costs, periodic amortization		(644)	(556)	(520)
Deferred policy acquisition costs, foreign currency translation		(2)	0	(3)
Deferred policy acquisition costs, ending balance		299	270	238
Annuity and Run-off Long-term Care and Life
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs, beginning balance		1,217	1,110	1,018
Deferred policy acquisition costs, additions		263	225	230
Deferred policy acquisition costs, periodic amortization		(238)	(161)	(169)
Deferred policy acquisition costs, annuity unlocking		29	34	25
Deferred policy acquisition costs, change included in realized gains		14	9	6
Deferred policy acquisition costs, ending balance		1,285	1,217	1,110
Movement in Deferred Sales Inducements [Roll Forward]
Deferred sales inducements, beginning balance		102	110	119
Deferred sales inducements, additions		2	4	9
Deferred sales inducements, periodic amortization		(19)	(19)	(24)
Deferred sales inducements, annuity unlocking		0	6	4
Deferred sales inducements, change included in realized gains		1	1	2
Deferred sales inducements, ending balance		86	102	110
Movement in Present Value of Future Insurance Profits [Roll Forward]
Present value of future profits, beginning balance		49	46	55
Present value of future profits, periodic amortization		(7)	(8)	(9)
Present value of future profits, annuity unlocking		0	1	0
Present value of future profits, other			10
Present value of future profits, ending balance		42	49	46
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	[1]	(422)	(265)	(234)
Unrealized investment gains (losses), change in unrealized	[1]	392	(157)	(31)
Unrealized investment gains (losses), ending balance	[1]	(30)	(422)	(265)
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		946	1,001	958
Deferred policy acquisition costs and present value of future profits, additions		265	229	239
Deferred policy acquisition costs and present value of future profits, periodic amortization		(264)	(188)	(202)
Deferred policy acquisition costs and present value of future profits, annuity unlocking		29	41	29
Deferred policy acquisition costs and present value of future profits, change included in realized gains		15	10	8
Deferred policy acquisition costs and present value of future profits, other			10
Deferred policy acquisition costs and present value of future profits, change in unrealized		392	(157)	(31)
Deferred policy acquisition costs and present value of future profits, ending balance		1,383	946	1,001
Excluding Unrealized Gains | Annuity and Run-off Long-term Care and Life
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		1,368	1,266	1,192
Deferred policy acquisition costs and present value of future profits, change in unrealized		0	0	0
Deferred policy acquisition costs and present value of future profits, ending balance		$ 1,413	$ 1,368	$ 1,266
[1]	Adjustments to DPAC related to net unrealized gains/losses on securities and cash flow hedges.

Managed Investment Entities - N

Managed Investment Entities - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)collateralizedloanobligation	Dec. 31, 2017USD ($)collateralizedloanobligation	Dec. 31, 2016USD ($)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	60.90%
Number of collateralized loan obligation entities | collateralizedloanobligation	15
Number of collateralized loan obligation entities formed during the period | collateralizedloanobligation	1	2	2
Face amount of managed investment entities liabilities purchased by subsidiaries after issuance date	$ 7	$ 71	$ 24
Amount paid by subsidiaries to purchase managed investment entities liabilities after issuance date	7	71	17
Proceeds received by subsidiaries related to sales and redemptions of managed investment entities liabilities	$ 45	$ 103	115
Number of collateralized loan obligation entities that were substantially liquidated during the period | collateralizedloanobligation	1	2
Difference between aggregate unpaid principal balance and fair value of CLOs' fixed maturity investments	$ 232	$ 55
Difference between aggregate unpaid principal balance and fair value of CLOs' debt	241	118
Carrying amount of CLO loans in default		1
Aggregate unpaid principal balance of CLO loans in default	0	8
Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
Aggregate fair value of investment in collateralized loan obligations	188	215	216
New collateralized loan obligation entities
Variable Interest Entity [Line Items]
Face value of liabilities issued by managed investment entities on issuance date	463	865	866
Face amount of managed investment entities liabilities purchased by subsidiaries at issuance date	31	$ 48	$ 64
Subordinated debt obligations | Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
Aggregate fair value of investment in collateralized loan obligations	$ 125

Managed Investment Entities - S

Managed Investment Entities - Selected financial information related to CLOs (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Gains (losses) on change in fair value of assets/liabilities:
Assets	[1]	$ (189)	$ (8)	$ 131
Liabilities	[1]	168	20	(116)
Management fees paid to AFG		16	18	17
CLO earnings (losses) attributable to AFG Shareholders	[2]	7	23	37
Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
Investment in CLO tranches		$ 188	$ 215	$ 216
[1]	Included in revenues in AFG’s Statement of Earnings.
[2]	Included in earnings before income taxes in AFG’s Statement of Earnings.

Goodwill and Other Intangible_2

Goodwill and Other Intangibles - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill acquired during period	$ 8	$ 8
Amortizable intangible assets related to property and casualty insurance acquisitions	54	54	$ 26
Accumulated amortization	39	39	30
Amortization of intangible assets		$ 9	$ 8	$ 8
Weighted average useful life of finite-lived intangible assets acquired		7 years
Future amortization of intangibles in next year	12	$ 12
Future amortization of intangibles in year two	12	12
Future amortization of intangibles in year three	6	6
Future amortization of intangibles in year four	4	4
Future amortization of intangibles in year five	4	4
Future amortization of intangibles after year five	$ 16	$ 16

Goodwill and Other Intangible_3

Goodwill and Other Intangibles - Changes in the carrying value of goodwill (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Changes in the carrying value of goodwill by reporting segment
Goodwill, Beginning balance	$ 207	$ 207	$ 199	$ 199	$ 199
Goodwill, acquisition of subsidiary	8	8
Goodwill, Ending balance	207	207
Property and Casualty
Changes in the carrying value of goodwill by reporting segment
Goodwill, Beginning balance	176	176	168	168	168
Goodwill, acquisition of subsidiary		8
Goodwill, Ending balance	176	176
Annuity
Changes in the carrying value of goodwill by reporting segment
Goodwill, Beginning balance	31	31	$ 31	$ 31	$ 31
Goodwill, acquisition of subsidiary		0
Goodwill, Ending balance	$ 31	$ 31

Long-Term Debt - Narrative (Det

Long-Term Debt - Narrative (Details) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 11, 2017	Nov. 30, 2017	Aug. 31, 2017	Jun. 30, 2017	Nov. 10, 2016	Aug. 31, 2016	Jun. 30, 2015
Long-term Debt, Fiscal Year Maturity [Abstract]
Scheduled principal payments on debt in next year		$ 0
Scheduled principal payments on debt in year two		0
Scheduled principal payments on debt in year three		0
Scheduled principal payments on debt in year four		0
Scheduled principal payments on debt in year five		0
Principal	$ 1,318,000,000	1,318,000,000	$ 1,318,000,000
Cash interest payments on long-term debt		59,000,000	85,000,000	$ 75,000,000
AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Revolving credit line		500,000,000
Amount borrowed under AFG revolving credit facility	0	$ 0	0
Interest rate description of fair value hedge activity		three-month LIBOR plus 8.099%
Interest rate description for revolving credit facility		1.00% to 1.875% (currently 1.375%) over LIBOR
LIBOR | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Interest rate on revolving debt facility		1.375%
LIBOR | AFG | Minimum
Long-term Debt, Fiscal Year Maturity [Abstract]
Interest rate on revolving debt facility		1.00%
LIBOR | AFG | Maximum
Long-term Debt, Fiscal Year Maturity [Abstract]
Interest rate on revolving debt facility		1.875%
Interest rate swaps | Fair Value Hedge | Designated as Hedging Instrument | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Cash interest received on long-term debt affiliated with interest rate swap			2,000,000	$ 3,000,000
Interest rate swaps | Fair Value Hedge | Designated as Hedging Instrument | LIBOR | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Basis spread on variable interest rate					8.099%
Senior Notes | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Principal	1,018,000,000	$ 1,018,000,000	1,018,000,000
Senior Notes | 4.50% Senior Notes due June 2047 | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Senior Notes, aggregate principal amount						$ 240,000,000		$ 350,000,000
Senior Notes, issuance price as a percentage of par value						102.374%		99.46%
Principal	590,000,000	$ 590,000,000	590,000,000
Interest rate on debt instruments		4.50%				4.50%		4.50%
Senior Notes | 3.50% Senior Notes due August 2026 | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Senior Notes, aggregate principal amount						$ 125,000,000				$ 300,000,000
Senior Notes, issuance price as a percentage of par value						99.698%				99.608%
Principal	425,000,000	$ 425,000,000	425,000,000
Interest rate on debt instruments		3.50%				3.50%				3.50%
Senior Notes | 9-7/8% Senior Notes due June 2019 | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Senior Notes, amount of the original debt instrument that was redeemed					$ 350,000,000
Senior Notes, amount of the original debt instrument that was redeemed plus a make-whole premium					$ 388,000,000
Interest rate on debt instruments					9.875%						9.875%
Senior Notes | 6-3/8% Senior Notes due June 2042 | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Senior Notes, amount of the original debt instrument that was redeemed								$ 230,000,000
Interest rate on debt instruments								6.375%
Senior Notes | 5-3/4% Senior Notes due August 2042 | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Senior Notes, amount of the original debt instrument that was redeemed							$ 125,000,000
Interest rate on debt instruments							5.75%
Subordinated Debt | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Principal	300,000,000	$ 300,000,000	300,000,000
Subordinated Debt | 6-1/4% Subordinated Debentures due September 2054 | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Principal	150,000,000	$ 150,000,000	150,000,000
Interest rate on debt instruments		6.25%
Subordinated Debt | 6% Subordinated Debentures due November 2055 | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Principal	150,000,000	$ 150,000,000	$ 150,000,000
Interest rate on debt instruments		6.00%
Revolving Credit Facility | National Interstate
Long-term Debt, Fiscal Year Maturity [Abstract]
Principal									$ 18,000,000
Revolving Credit Facility | Line of Credit | National Interstate
Long-term Debt, Fiscal Year Maturity [Abstract]
Principal									$ 6,000,000
Make-whole premium | Senior Notes | 9-7/8% Senior Notes due June 2019 | AFG
Long-term Debt, Fiscal Year Maturity [Abstract]
Make-whole premium included in the loss on the retirement of debt	$ (38,000,000)

Long-Term Debt - Schedule of lo

Long-Term Debt - Schedule of long-term debt (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Summary of Carrying value of long-term debt
Principal	$ 1,318	$ 1,318
Discount and Issue Costs	(16)	(17)
Carrying Value	1,302	1,301
AFG
Summary of Carrying value of long-term debt
Carrying Value	1,302	1,301
Senior Notes | AFG
Summary of Carrying value of long-term debt
Principal	1,018	1,018
Discount and Issue Costs	(6)	(7)
Carrying Value	1,012	1,011
Senior Notes | 4.50% Senior Notes due June 2047 | AFG
Summary of Carrying value of long-term debt
Principal	590	590
Discount and Issue Costs	(2)	(2)
Carrying Value	588	588
Senior Notes | 3.50% Senior Notes due August 2026 | AFG
Summary of Carrying value of long-term debt
Principal	425	425
Discount and Issue Costs	(4)	(5)
Carrying Value	421	420
Senior Notes | Other | AFG
Summary of Carrying value of long-term debt
Principal	3	3
Discount and Issue Costs	0	0
Carrying Value	3	3
Subordinated Debentures | AFG
Summary of Carrying value of long-term debt
Principal	300	300
Discount and Issue Costs	(10)	(10)
Carrying Value	290	290
Subordinated Debentures | 6-1/4% Subordinated Debentures due September 2054 | AFG
Summary of Carrying value of long-term debt
Principal	150	150
Discount and Issue Costs	(5)	(5)
Carrying Value	145	145
Subordinated Debentures | 6% Subordinated Debentures due November 2055 | AFG
Summary of Carrying value of long-term debt
Principal	150	150
Discount and Issue Costs	(5)	(5)
Carrying Value	$ 145	$ 145

Shareholders' Equity - Narrativ

Shareholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Dec. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
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				$ 57	$ 65	$ 38
Cash received from the exercise of stock options				29	34	32
Tax benefit related to exercise of stock options				9	18	11
Total compensation expense related to stock incentive plans				23	30	28
Tax benefit related to compensation costs				13	27	19
Net of tax unrealized gains (losses) related to credit-only impaired securities	$ 68			$ 58	68	$ 52
Impact of the U.S. corporate tax rate change on AOCI	4				$ 4
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Common Stock vesting period				3 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Common Stock vesting period				4 years
Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock reserved for issuance under stock incentive plans (shares)				7,000,000
Common Stock options issued under stock incentive plan (shares)				0	0	0
Annual Equity Bonus Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other benefit plans, shares issued (shares)		45,804	47,826
Common Stock issued, fair value per share (USD per share)		$ 115.49	$ 96.13
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to equity-based awards that have yet to vest				$ 3
Weighted average period of cost expected to be recognized				1 year
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted Common Stock vested during period, fair value				$ 10	$ 14	$ 10
Unrecognized compensation expense related to equity-based awards that have yet to vest				$ 35
Weighted average period of cost expected to be recognized				2 years 6 months
Accounting Standards Update 2018-02 | Tax Cuts and Jobs Act of 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax Cuts and Jobs Act of 2017, Reclassification from AOCI to Retained Earnings, Tax Effect	$ 145
Equity securities | Accounting Standards Update 2016-01
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Impact of the U.S. corporate tax rate change on AOCI							$ (221)

Shareholders' Equity - Preferre

Shareholders' Equity - Preferred stock authorized for issuance (Details)	Dec. 31, 2018$ / sharesshares
Voting Preferred Stock
Class of Stock [Line Items]
Preferred Stock, par value | $ / shares	$ 0
Preferred Stock, shares authorized | shares	12,500,000
Nonvoting Preferred Stock
Class of Stock [Line Items]
Preferred Stock, par value | $ / shares	$ 0
Preferred Stock, shares authorized | shares	12,500,000

Shareholders' Equity - Data rel

Shareholders' Equity - Data relating to grants of restricted stock (Details) - Restricted Stock	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at January 1, 2018 | shares	759,035
Granted | shares	200,625
Vested | shares	(86,177)
Forfeited | shares	(7,553)
Outstanding at December 31, 2018 | shares	865,930
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 | $ / shares	$ 73.40
Average grant date fair value, Granted | $ / shares	112.86
Average grant date fair value, Vested | $ / shares	56.89
Average grant date fair value, Forfeited | $ / shares	87.47
Average grant date fair value, Outstanding, Ending balance | $ / shares	$ 84.06

Shareholders' Equity - Data for

Shareholders' Equity - Data for stock options issued under the stock incentive plans (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at January 1, 2018 | shares	3,467,340
Exercised | shares	(778,270)
Forfeited/Cancelled | shares	(21,628)
Outstanding at December 31, 2018 | shares	2,667,442
Options exercisable at December 31, 2018 | shares	2,253,003
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Average exercise price, Beginning balance | $ / shares	$ 45.80
Average exercise price, Exercised | $ / shares	37.66
Average exercise price, Forfeited/Cancelled | $ / shares	42.10
Average exercise price, Ending balance | $ / shares	48.20
Average exercise price, Options exercisable | $ / shares	$ 45.95
Average remaining contractual term, Options outstanding	4 years 2 months 12 days
Average remaining contractual term, Options exercisable	3 years 10 months 24 days
Aggregate intrinsic value, Options outstanding | $	$ 113
Aggregate intrinsic value, Options exercisable | $	$ 100

Shareholders' Equity - Progress

Shareholders' Equity - Progression of the components of accumulated other comprehensive income (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016	Jan. 01, 2018
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance			$ 813
Other comprehensive income (loss), net of tax			(544)		$ 296		$ 67
Cumulative effect of accounting change		$ 4			4
Other comprehensive income (loss), net of tax, acquisition of noncontrolling interest							(315)
AOCI ending balance		813	48		813
Accumulated net investment gain (loss) including portion attributable to noncontrolling interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), unrealized holding gains on securities arising during the period, Pretax			(689)		456		124
Other comprehensive income (loss), unrealized holding gains on securities arising during the period, tax			145		(159)		(44)
Other comprehensive income (loss), unrealized holding gains on securities arising during the period, net of tax			(544)		297		80
Reclassification from accumulated other comprehensive income, pretax	[1]		10		(15)		(19)
Reclassification from accumulated other comprehensive income, tax	[1]		(2)		5		7
Reclassification from accumulated other comprehensive income, net of tax			8		(10)		(12)
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), pretax			(679)		441		105
Other comprehensive income (loss), tax			143		(154)		(37)
Other comprehensive income (loss), net of tax			(536)		287		68
Accumulated net investment gain (loss) attributable to noncontrolling interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), unrealized holding gains on securities arising during the period, net of tax			0		0		(4)
Reclassification from accumulated other comprehensive income, net of tax	[1]		0		0		(1)
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), net of tax			0		0		(5)
Accumulated net investment gain (loss) attributable to parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), unrealized holding gains on securities arising during the period, net of tax			(544)		297		76
Reclassification from accumulated other comprehensive income, net of tax			8		(10)		(13)
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance			840	[2]	404	[2]	332
Other comprehensive income (loss), net of tax			(536)		287		63
Cumulative effect of accounting change	[3]							$ (221)
Other comprehensive income (loss), net of tax, acquisition of noncontrolling interest	[3]						9
AOCI ending balance	[2]	840	83		840		404
Accumulated net gain (loss) from cash flow hedges including portion attributable to noncontrolling interest
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), pretax			2		(6)		(12)
Other comprehensive income (loss), tax			0		2		4
Other comprehensive income (loss), net of tax			2		(4)		(8)
Accumulated net gain (loss) from cash flow hedges attributable to noncontrolling interest
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), net of tax			0		0		0
Accumulated net gain (loss) from cash flow hedges attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance			(13)		(7)		1
Other comprehensive income (loss), net of tax			2		(4)		(8)
Cumulative effect of accounting change	[3]							0
AOCI ending balance		(13)	(11)		(13)		(7)
Accumulated foreign currency adjustment including portion attributable to noncontrolling interest
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), pretax			(9)		9		6
Other comprehensive income (loss), tax			(1)		3		1
Other comprehensive income (loss), net of tax			(10)		12		7
Accumulated foreign currency adjustment attributable to noncontrolling interest
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), net of tax			0		0		0
Accumulated foreign currency adjustment attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance			(6)		(15)		(22)
Other comprehensive income (loss), net of tax			(10)		12		7
Cumulative effect of accounting change	[3]							0
AOCI ending balance		(6)	(16)		(6)		(15)
Accumulated defined benefit plans adjustment including portion attributable to noncontrolling interest
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), pretax			0		1		0
Other comprehensive income (loss), tax			0		0		0
Other comprehensive income (loss), net of tax			0		1		0
Accumulated defined benefit plans adjustment attributable to noncontrolling interest
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), net of tax			0		0		0
Accumulated defined benefit plans adjustment attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance			(8)		(7)		(7)
Other comprehensive income (loss), net of tax			0		1		0
Cumulative effect of accounting change	[3]							0
AOCI ending balance		(8)	(8)		(8)		(7)
AOCI including portion attributable to noncontrolling interest
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), pretax			(686)		445		99
Other comprehensive income (loss), tax			142		(149)		(32)
Other comprehensive income (loss), net of tax			(544)		296		67
AOCI attributable to noncontrolling interest
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss), net of tax			0		0		(5)
AOCI attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
AOCI beginning balance			813		375		304
Other comprehensive income (loss), net of tax			(544)		296		62
Cumulative effect of accounting change		(221)			(221)			$ (221)	[3]
Other comprehensive income (loss), net of tax, acquisition of noncontrolling interest	[3]						9
AOCI ending balance		813	$ 48		$ 813		$ 375
Tax Cuts and Jobs Act of 2017 | Accumulated net investment gain (loss) attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
Tax Cuts and Jobs Act of 2017, Reclassification from AOCI to Retained Earnings, Tax Effect	[3]	149
Tax Cuts and Jobs Act of 2017 | Accumulated net gain (loss) from cash flow hedges attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
Tax Cuts and Jobs Act of 2017, Reclassification from AOCI to Retained Earnings, Tax Effect	[3]	(2)
Tax Cuts and Jobs Act of 2017 | Accumulated defined benefit plans adjustment attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
Tax Cuts and Jobs Act of 2017, Reclassification from AOCI to Retained Earnings, Tax Effect	[3]	(2)
Tax Cuts and Jobs Act of 2017 | AOCI attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
Tax Cuts and Jobs Act of 2017, Reclassification from AOCI to Retained Earnings, Tax Effect	[3]	142
Redeemable noncontrolling interest | Tax Cuts and Jobs Act of 2017 | Accumulated foreign currency adjustment attributable to parent
Accumulated Other Comprehensive Income [Roll Forward]
Tax Cuts and Jobs Act of 2017, Reclassification from AOCI to Retained Earnings, Tax Effect	[3]	$ (3)
[1]	The reclassification adjustment out of net unrealized gains on securities affected the following lines in AFG’s Statement of Earnings: OCI component Affected line in the statement of earnings Pretax Realized gains (losses) on securities Tax Provision for income taxes Attributable to noncontrolling interests Net earnings attributable to noncontrolling interests
[2]	Includes net unrealized gains of $58 million at December 31, 2018 compared to net unrealized gains of $68 million and $52 million at December 31, 2017 and 2016, related to securities for which only the credit portion of an other-than-temporary impairment has been recorded in earnings.
[3]	On January 1, 2018, AFG adopted new guidance that requires all equity securities other than those accounted for under the equity method to be reported at fair value with holding gains and losses recognized in net earnings. At the date of adoption, the $221 million net unrealized gain on equity securities classified as available for sale (with unrealized holding gains and losses reported in AOCI) under the prior guidance was reclassified from AOCI to retained earnings as the cumulative effect of an accounting change. Other also includes the December 2017 reclassification of $145 million stranded in AOCI from accounting for the Tax Cuts and Jobs Act of 2017 to retained earnings (see Note A — “Accounting Policies — Income Taxes”), the impact on AOCI of the December 2017 sale of redeemable noncontrolling interests in Neon and the November 2016 acquisition of the noncontrolling interest in NATL (see Note B — “Acquisitions and Sale of Businesses”).

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) £ in Millions, $ in Millions		Jan. 01, 2018	Jan. 31, 2008USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2018GBP (£)
Income Tax Reconciliation [Line Items]
Statutory rate of income taxes						21.00%	35.00%	35.00%
Payments to acquire additional interest in subsidiaries						$ 0	$ 0	$ 315
Impact of foreign operations included in the provision for income taxes						(2)	21	5
Decrease in the valuation allowance related to the change in the U.S. corporate tax rate						11	(7)	52
Income tax expense (benefit)						122	247	119
Decrease in net deferred tax assets resulting from the changes in the Tax Cuts and Jobs Act of 2017						0	$ 83	$ 0
Effective tax rate excluding the charge related to the exit of certain lines of business within subsidiaries and impact of the change in the U.S. corporate tax rate							31.00%
Effective tax rate excluding the charge related to the exit of certain lines of business within subsidiaries, acquisition of the noncontrolling interest, and restructuring of subsidiaries								35.00%
Income (losses) subject to tax in foreign jurisdictions						(69)	$ (58)	$ (160)
Operating loss carryforwards, valuation allowance						23
Cash payments for income taxes						$ 156	194	308
Limitation on the use of tax credit carryforwards						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. Approximately $19 million of AFG’s SRLY NOLs expired unutilized at December 31, 2018.
Tax Cuts and Jobs Act implementation complete						true
AFG
Income Tax Reconciliation [Line Items]
Income tax expense (benefit)				$ (56)		$ 122	247	119
National Interstate
Income Tax Reconciliation [Line Items]
Income tax expense (benefit)					$ (66)
Neon Capital Limited
Income Tax Reconciliation [Line Items]
Income tax expense (benefit)				(56)	(111)			(48)
Increase (Decrease) in current taxes payable				(20)	$ (29)
Charge for valuation allowance
Income Tax Reconciliation [Line Items]
Charge for valuation allowance against deferred tax assets						93
Maximum | AFG
Income Tax Reconciliation [Line Items]
Unrecognized tax benefits that would impact the effective tax rate				1		1	1
Interest included in tax provision						1	1	1
Decrease in related accrued interest (are less than in 2017 and 2016)				1			1
Amount of expense for penalties related to a tax position						1	1	1
Income tax penalties accrued				1		1	1
Amount unutilized
Income Tax Reconciliation [Line Items]
Operating loss carryforwards						19
Tax Cuts and Jobs Act of 2017
Income Tax Reconciliation [Line Items]
Statutory rate of income taxes		21.00%
Decrease in net deferred tax assets resulting from the changes in the Tax Cuts and Jobs Act of 2017				$ 83
Tax Cuts and Jobs Act of 2017 | Neon Capital Limited
Income Tax Reconciliation [Line Items]
Decrease in the valuation allowance related to the change in the U.S. corporate tax rate							(61)
United Kingdom
Income Tax Reconciliation [Line Items]
Operating loss carryforwards	[1]					$ 215					£ 168
Property and casualty insurance
Income Tax Reconciliation [Line Items]
Change in AFG’s liability for uncertain tax positions due to the uncertainty in state taxation									$ 1
Tax payments due to resolved uncertainty in state taxation							1
Property and casualty insurance | Other lines
Income Tax Reconciliation [Line Items]
Special charges related to the exit of certain lines of business within subsidiaries								65
Property and casualty insurance | Other lines | Neon Capital Limited
Income Tax Reconciliation [Line Items]
Special charges related to the exit of certain lines of business within subsidiaries								$ 65
Neon Capital Limited
Income Tax Reconciliation [Line Items]
Payments to acquire controlling interest in subsidiaries			$ 75
Percentage ownership of subsidiary			67.00%
Payments to acquire additional interest in subsidiaries										$ 17
Foreign underwriting losses
Income Tax Reconciliation [Line Items]
Impact of foreign operations included in the provision for income taxes							$ 14
[1]	£168 million

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of income taxes at the statutory rate to the provision for income taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Earnings before income taxes (“EBT”)	$ 639	$ 724	$ 787
Income taxes at statutory rate	134	253	275
Effect of tax exempt interest	(13)	(23)	(24)
Effect of adjustments to prior year taxes	(8)	(4)	(2)
Effect of stock-based compensation	(8)	(16)	(9)
Effect of dividends received deduction	(4)	(8)	(7)
Effect of employee stock ownership plan dividend paid deduction	(3)	(5)	(2)
Effect of foreign operations	(2)	21	5
Effect of change in valuation allowance (excluding change in tax rate)	11	(7)	52
Effect of nondeductible expenses	7	6	7
Effect of Neon restructuring	0	(56)	(111)
Effective of change in U.S. corporate tax rate	0	83	0
Effect of acquisition of noncontrolling interest	0	0	(66)
Effect of subsidiaries not in AFG's tax return	0	0	3
Effect of other income tax reconciliation	8	3	(2)
Provision for income taxes as shown in the Statement of Earnings	$ 122	$ 247	$ 119
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Income taxes at statutory rate as a percentage of EBT	21.00%	35.00%	35.00%
Effect of tax exempt interest as a percentage of EBT	(2.00%)	(3.00%)	(3.00%)
Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Percent	(1.00%)	(1.00%)	0.00%
Effect of stock-based compensation as a percentage of EBT	(1.00%)	(2.00%)	(1.00%)
Effect of dividend received deduction as a percentage of EBT	(1.00%)	(1.00%)	(1.00%)
Effect of employee stock ownership plan dividend paid deduction as a percentage of EBT	(1.00%)	(1.00%)	(0.00%)
Effect of foreign operations as a percentage of EBT	0.00%	3.00%	0.00%
Effect of change in valuation allowance (excluding change in tax rate) as a percentage of EBT	2.00%	(1.00%)	7.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	1.00%	1.00%	1.00%
Effect of Neon restructuring as a percentage of EBT	0.00%	(8.00%)	(14.00%)
Effective of change in U.S. corporate tax rate as a percentage of EBT	0.00%	11.00%	0.00%
Effect of acquisition of noncontrolling interest as a percentage of EBT	0.00%	0.00%	(8.00%)
Effect of subsidiaries not in AFG's tax return as a percentage of EBT	0.00%	0.00%	0.00%
Effect of other income tax reconciliation as a percentage of EBT	1.00%	1.00%	(1.00%)
Provision for income taxes as shown in the Statement of Earnings as a percentage of EBT	19.00%	34.00%	15.00%

Income Taxes - Total income tax

Income Taxes - Total income tax provision (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current taxes:
Federal	$ 196	$ 153	$ 299
State	8	6	12
Deferred taxes:
Federal	(82)	5	(192)
Impact of change in U.S. corporate tax rate	0	83	0
Total Federal deferred taxes	(82)	88	(192)
Provision for income taxes as shown in the Statement of Earnings	$ 122	$ 247	$ 119

Income Taxes - Operating and ca

Income Taxes - Operating and capital loss carryforwards available (Details) - Dec. 31, 2018 £ in Millions, $ in Millions		USD ($)	GBP (£)
U.S. | Expiring 2019 - 2022
Operating and capital loss carryforwards [Line Items]
Operating loss carryforwards		$ 112
United Kingdom
Operating and capital loss carryforwards [Line Items]
Operating loss carryforwards	[1]	$ 215	£ 168
[1]	£168 million

Income Taxes - Significant comp

Income Taxes - Significant components of deferred tax assets and liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Federal net operating loss carryforwards	$ 23	$ 27
Foreign underwriting losses	93	80
Capital loss carryforwards	0	32
Insurance claims and reserves	743	694
Employee benefits	88	84
Other, net	44	45
Total deferred tax assets before valuation allowance	991	962
Valuation allowance against deferred tax assets	(119)	(109)
Total deferred tax assets	872	853
Deferred tax liabilities:
Investment securities	(70)	(341)
Deferred policy acquisition costs	(291)	(202)
Insurance claims and reserves transition liability	(110)	(128)
Real estate, property and equipment	(36)	(35)
Total deferred tax liabilities	(507)	(706)
Net deferred tax asset (liability)	365	147
Excluding Unrealized Gains
Deferred tax assets:
Federal net operating loss carryforwards	23	27
Foreign underwriting losses	93	80
Capital loss carryforwards	0	32
Insurance claims and reserves	740	665
Employee benefits	88	84
Other, net	44	48
Total deferred tax assets before valuation allowance	988	936
Valuation allowance against deferred tax assets	(119)	(109)
Total deferred tax assets	869	827
Deferred tax liabilities:
Investment securities	(36)	(1)
Deferred policy acquisition costs	(300)	(293)
Insurance claims and reserves transition liability	(110)	(128)
Real estate, property and equipment	(36)	(35)
Total deferred tax liabilities	(482)	(457)
Net deferred tax asset (liability)	387	370
Impact of Unrealized Gains
Deferred tax assets:
Federal net operating loss carryforwards	0	0
Foreign underwriting losses	0	0
Capital loss carryforwards	0	0
Insurance claims and reserves	3	29
Employee benefits	0	0
Other, net	0	(3)
Total deferred tax assets before valuation allowance	3	26
Valuation allowance against deferred tax assets	0	0
Total deferred tax assets	3	26
Deferred tax liabilities:
Investment securities	(34)	(340)
Deferred policy acquisition costs	9	91
Insurance claims and reserves transition liability	0	0
Real estate, property and equipment	0	0
Total deferred tax liabilities	(25)	(249)
Net deferred tax asset (liability)	$ (22)	$ (223)

Income Taxes - Progression of t

Income Taxes - Progression of the liability for uncertain tax positions, excluding interest and penalties (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Progression of the liability for uncertain tax positions, excluding interest and penalties
Balance at January 1	$ 0	$ 1	$ 1
Additions for tax positions of prior years	0	0	0
Reductions for tax positions of prior years	0	0	0
Additions for tax positions of current year	0	0	0
Settlements	0	(1)	0
Balance at December 31	$ 0	$ 0	$ 1

Contingencies - Narrative (Deta

Contingencies - Narrative (Details) - USD ($) $ in Millions	Dec. 24, 2015	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loss Contingencies [Line Items]
Reinsurance recoverables on asbestos and environmental reserves, net of allowance					$ 2,942	$ 2,957	$ 2,302	$ 2,201
Property and Casualty Group
Loss Contingencies [Line Items]
Increase in asbestos and environmental reserves		$ 18	$ 89	$ 36
Liability for asbestos and environmental reserves					524
Former railroad and manufacturing operations
Loss Contingencies [Line Items]
Increase in asbestos and environmental reserves		$ 9	$ 24	$ 5
American Premier and its subsidiaries
Loss Contingencies [Line Items]
Liability for environmental and other claims					83
GAFRI
Loss Contingencies [Line Items]
Liability for environmental and other claims					8
Run-off long-term care and life
Loss Contingencies [Line Items]
Contingent capital support agreement amount	$ 35
Contingent capital support agreement term	5 years
A&E reserves | Property and Casualty Group
Loss Contingencies [Line Items]
Reinsurance recoverables on asbestos and environmental reserves, net of allowance					$ 129

Quarterly Operating Results (_3

Quarterly Operating Results (Unaudited) - Quarterly results of consolidated operations (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Statement of Earnings
Revenues	$ 1,690	$ 2,008	$ 1,833	$ 1,619	$ 1,808	$ 1,835	$ 1,646	$ 1,576	$ 7,150	$ 6,865	$ 6,498
Net earnings, including noncontrolling interests	(35)	203	208	141	166	11	145	155	517	477	668
Net earnings (losses) attributable to shareholders	$ (29)	$ 204	$ 210	$ 145	$ 166	$ 11	$ 145	$ 153	$ 530	$ 475	$ 649
Earnings Attributable to Shareholders per Common Share:
Basic (USD per share)	$ (0.33)	$ 2.30	$ 2.36	$ 1.64	$ 1.88	$ 0.13	$ 1.64	$ 1.76	$ 5.95	$ 5.40	$ 7.47
Diluted (USD per share)	$ (0.33)	$ 2.26	$ 2.31	$ 1.60	$ 1.84	$ 0.13	$ 1.61	$ 1.72	$ 5.85	$ 5.28	$ 7.33
Average number of Common Shares:
Basic (shares)	89.3	89.1	89	88.6	88.2	88.1	87.8	87.2	89	87.8	86.9
Diluted (shares)	89.3	90.7	90.7	90.4	90.1	90	89.8	89.3	90.6	89.8	88.5

Quarterly Operating Results (_4

Quarterly Operating Results (Unaudited) - Realized gains, favorable (adverse) prior year development of the liability for losses and LAE and the impact of derivatives related to Fixed-indexed annuities (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Realized gains (losses) and favorable (adverse) development on unpaid loss and loss adjustment expenses
Realized Gains (Losses) on Securities and Subsidiaries	$ (15)	$ 1	$ 8	$ 2	$ 6	$ (12)	$ 8	$ 3	$ (4)	$ 5
Prior Year Development Favorable (Adverse)	61	31	44	56	66	(52)	22	28	192	64
Impact of derivatives related to FIAs	(47)	(2)	3	13	$ (11)	$ (4)	$ (16)	$ (2)	(33)	$ (33)
Equity securities | Accounting Standards Update 2016-01
Realized gains (losses) and favorable (adverse) development on unpaid loss and loss adjustment expenses
Realized Gains (Losses) on Securities and Subsidiaries	$ (223)	$ 33	$ 23	$ (95)					$ (262)

Quarterly Operating Results (_5

Quarterly Operating Results (Unaudited) - Narrative (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Operating Results (Unaudited) [Line Items]
S&P 500 Index increase (decrease) during period	(14.00%)
Pretax catastrophe losses					$ 107				$ 103	$ 140
Income tax expense (benefit)									122	247	$ 119
Property and casualty insurance | Other lines
Quarterly Operating Results (Unaudited) [Line Items]
Special charges to increase asbestos and environmental reserves		$ 18			89				18	89	36
Favorable reserve development related to certain lines of business within subsidiaries in connection with a reinsurance to close agreement										18
Property and casualty insurance | Real estate investment
Quarterly Operating Results (Unaudited) [Line Items]
Pretax income from the sale of real estate properties included in other income							$ 13				32
Annuity
Quarterly Operating Results (Unaudited) [Line Items]
S&P 500 impact on annuity earnings before income taxes beyond the impact of derivatives	$ (30)
Other
Quarterly Operating Results (Unaudited) [Line Items]
Special charges to increase asbestos and environmental reserves									9	24	5
Write off of deferred debt issuance cost due to the retirement of debt					4	$ 7
Make-whole premium, settlement of interest rate swap and write off of deferred debt issuance cost included in the loss on the retirement of debt				$ 40						51
Other | Former railroad and manufacturing operations
Quarterly Operating Results (Unaudited) [Line Items]
Special charges to increase asbestos and environmental reserves		$ 9			$ 24
Neon Capital Limited
Quarterly Operating Results (Unaudited) [Line Items]
Income tax expense (benefit)				(56)				$ (111)			(48)
Neon Capital Limited | Property and casualty insurance
Quarterly Operating Results (Unaudited) [Line Items]
Favorable reserve development related to certain lines of business within subsidiaries in connection with a reinsurance to close agreement				42
Neon Capital Limited | Property and casualty insurance | Other lines
Quarterly Operating Results (Unaudited) [Line Items]
Favorable reserve development related to certain lines of business within subsidiaries in connection with a reinsurance to close agreement				18
Neon Capital Limited | Neon Capital Limited | Current lines
Quarterly Operating Results (Unaudited) [Line Items]
Favorable reserve development related to certain lines of business within subsidiaries in connection with a reinsurance to close agreement				24
AFG
Quarterly Operating Results (Unaudited) [Line Items]
Income tax expense (benefit)				(56)					122	$ 247	$ 119
Annuity benefits | Annuity
Quarterly Operating Results (Unaudited) [Line Items]
Charges resulting from updating (unlocking) actuarial assumptions	4		$ 27	$ 3
Equity securities | Accounting Standards Update 2016-01 | Equity securities still owned
Quarterly Operating Results (Unaudited) [Line Items]
Net holding gains (losses) on equity securities									(257)
Equity securities | Accounting Standards Update 2016-01 | Equity securities still owned | Realized gains (losses) on securities
Quarterly Operating Results (Unaudited) [Line Items]
Net holding gains (losses) on equity securities	$ (228)								$ (279)

Insurance - Narrative (Details)

Insurance - Narrative (Details) - USD ($) $ in Millions	3 Months Ended					12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Insurance [Line Items]
Carrying value of cash and securities owned by U.S.-based insurance subsidiaries on deposit	$ 1,060					$ 1,060
Carrying value of cash and securities owned by insurance subsidiaries on deposit in support of underwriting activities at Lloyd's	118					118
Undrawn letters of credit	296					296
Undrawn letters of credit, collateralized	0					$ 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	13		$ 15			$ 13	$ 15
Long-term care insurance reserves, net of reinsurance recoverables	45		39			45	39
Investment in Federal Home Loan Bank capital stock	47					47
Advances from Federal Home Loan Bank	1,100					$ 1,100
Proceeds from Federal Home Loan Bank Advance, Investing Activities	225
Description of variable rate basis						LIBOR
Repayments of advances from Federal Home Loan Bank due in next twelve months	445					$ 445
Repayments of advances from Federal Home Loan Bank due in year two	40					40
Repayments of advances from Federal Home Loan Bank due in year three	611					611
Fair value of fixed maturity investments held as collateral by the Federal Home Loan Bank	1,280					1,280
Interest on advances from Federal Home Loan Bank						20	14	$ 8
Maximum amount of dividends available to be paid by insurance subsidiaries to AFG without prior approval of regulatory authorities	1,300					1,300
Dividends on common stock						(397)	(421)	(187)
Aggregate guaranteed minimum death benefit value on variable annuity polices in force	35		15			$ 35	15
Minimum | LIBOR
Insurance [Line Items]
FHLB advances, basis spread on variable rate						0.15%
Maximum
Insurance [Line Items]
Dividends payments without violating the most restrictive debt covenants, minimum	2,000					$ 2,000
Maximum | LIBOR
Insurance [Line Items]
FHLB advances, basis spread on variable rate						0.24%
Average | LIBOR
Insurance [Line Items]
FHLB advances, basis spread on variable rate						2.68%
FHLB, advances, refinanced terms
Insurance [Line Items]
Advances from Federal Home Loan Bank	40		831			$ 40	831
Catastrophe Bonds
Insurance [Line Items]
Catastrophe reinsurance coverage, excess retention percentage						95.00%
Catastrophe reinsurance coverage, excess retention amount						$ 200
Catastrophe reinsurance coverage, retention amount						104
Catastrophe reinsurance coverage, annual cost						11
Life insurance
Insurance [Line Items]
Increased statutory surplus resulting from reinsurance treaty	2,701		2,132			2,701	2,132
Life insurance in force, ceded premiums	7,690		8,320			7,690	8,320
Life insurance in force, direct premiums	10,820		12,050			10,820	12,050
Reinsurance ceded						22	28	31
Reinsurance recoveries						38	35	41
Variable annuities | Maximum
Insurance [Line Items]
Death benefits paid in excess of the variable annuity account balances (are less than in 2016, 2017 and 2018)						1	1	1
Property and casualty insurance | Other lines
Insurance [Line Items]
Special charges to increase asbestos and environmental reserves		$ 18		$ 89		18	89	36
Favorable reserve development related to certain lines of business within subsidiaries in connection with a reinsurance to close agreement							$ 18
Special charges related to the exit of certain lines of business within subsidiaries								65
Property and casualty insurance | Other lines | Increased insurance loss reserves related to medical malpractice and general liability lines
Insurance [Line Items]
Special charges related to the exit of certain lines of business within subsidiaries					$ 57
Neon Capital Limited | Property and casualty insurance
Insurance [Line Items]
Favorable reserve development related to certain lines of business within subsidiaries in connection with a reinsurance to close agreement			42
Neon Capital Limited | Property and casualty insurance | Other lines
Insurance [Line Items]
Favorable reserve development related to certain lines of business within subsidiaries in connection with a reinsurance to close agreement			18
Special charges related to the exit of certain lines of business within subsidiaries								$ 65
Neon Capital Limited | Property and casualty insurance | Other lines | Reinsurance to close agreement
Insurance [Line Items]
Favorable reserve development related to certain lines of business within subsidiaries in connection with a reinsurance to close agreement			18
Neon Capital Limited | Neon Capital Limited | Current lines
Insurance [Line Items]
Favorable reserve development related to certain lines of business within subsidiaries in connection with a reinsurance to close agreement			$ 24
Great American Life Insurance Company | Life insurance
Insurance [Line Items]
Increased statutory surplus resulting from reinsurance treaty	$ 510					$ 510

Insurance - Analysis of changes

Insurance - Analysis of changes in the liability for losses and loss adjustment expenses, net of reinsurance (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Analysis of changes in the liability for losses and loss adjustment expenses, net of reinsurance
Balance at beginning of period				$ 9,678				$ 8,563	$ 9,678		$ 8,563	$ 8,127
Less reinsurance recoverables, net of allowance	$ 2,942				$ 2,957				2,942		2,957	2,302		$ 2,201
Net liability at beginning of period				6,721				6,261	6,721		6,261	5,926
Liability for losses and loss adjustment expenses, period increase (decrease) [Abstract]
Provision for losses and LAE occurring in the current year									3,195		3,019	2,730
Net increase (decrease) in the provision for claims of prior years:
Provision for claims of prior years related to special A&E charges, Neon exited lines development and other	(61)	$ (31)	$ (44)	$ (56)	(66)	$ 52	$ (22)	$ (28)	(192)		(64)
Total losses and LAE incurred									3,003		2,955	2,762
Payments for losses and LAE of:
Current year									(963)		(942)	(841)
Prior years									(1,639)		(1,586)	(1,512)
Total payments									(2,602)		(2,528)	(2,353)
Reserves of businesses disposed									(319)	[1]	0	(40)	[1]
Foreign currency translation and other									(4)		33	(34)
Net liability at end of period	6,799				6,721				6,799		6,721	6,261
Add back reinsurance recoverables, net of allowance	2,942				2,957				2,942		2,957	2,302
Gross unpaid losses and LAE included in the balance sheet	$ 9,741				$ 9,678				9,741		9,678	8,563
Special A&E charges
Net increase (decrease) in the provision for claims of prior years:
Provision for claims of prior years related to special A&E charges, Neon exited lines development and other									18		89	36
Neon exited lines charge
Net increase (decrease) in the provision for claims of prior years:
Provision for claims of prior years related to special A&E charges, Neon exited lines development and other									0		(18)	57
Other
Net increase (decrease) in the provision for claims of prior years:
Provision for claims of prior years related to special A&E charges, Neon exited lines development and other									$ (210)		$ (135)	$ (61)
[1]	Reflects the reinsurance to close transactions at Neon (discussed below).

Insurance - Reconciliation of i

Insurance - Reconciliation of incurred and paid claims development information to the aggregate carrying amount of the liability for unpaid losses and LAE (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Total reserves, net of reinsurance	$ 6,799	$ 6,721	$ 6,261	$ 5,926
Add back reinsurance recoverables, net of allowance	(2,942)	(2,957)	(2,302)	(2,201)
Gross unpaid losses and LAE included in the balance sheet	9,741	$ 9,678	$ 8,563	$ 8,127
Property and casualty insurance
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Specialty unpaid losses and LAE, net of reinsurance	5,506
Other unpaid losses and LAE, net of reinsurance	1,293
Unallocated LAE	335
Total reserves, net of reinsurance	6,799
Add back reinsurance recoverables, net of allowance	2,942
Gross unpaid losses and LAE included in the balance sheet	9,741
Property and casualty insurance | Reserves for foreign operations:
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Other unpaid losses and LAE, net of reinsurance	268
Property and casualty insurance | A&E reserves
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Other unpaid losses and LAE, net of reinsurance	395
Property and casualty insurance | Other
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Other unpaid losses and LAE, net of reinsurance	30
Property and casualty insurance | Property and transportation
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Specialty unpaid losses and LAE, net of reinsurance	1,117
Property and casualty insurance | Specialty casualty
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Specialty unpaid losses and LAE, net of reinsurance	3,884
Property and casualty insurance | Specialty financial
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Specialty unpaid losses and LAE, net of reinsurance	225
Property and casualty insurance | Other specialty
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Specialty unpaid losses and LAE, net of reinsurance	280
Neon Capital Limited | Property and casualty insurance | Reserves for foreign operations:
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Other unpaid losses and LAE, net of reinsurance	$ 265

Insurance - Short-duration insu

Insurance - Short-duration insurance contracts, claims development (Details) - Property and casualty insurance $ in Millions		Dec. 31, 2018USD ($)claim	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 19,905
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		14,960
Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE)		561
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE)		5,506
Accident Year 2009
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		1,519	$ 1,529	$ 1,539	$ 1,543	$ 1,545	$ 1,552	$ 1,566	$ 1,596	$ 1,607	$ 1,624
Total IBNR Plus Expected Development on Reported Claims		$ 43
Cumulative Number of Reported Claims | claim		222,664
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 1,445	1,435	1,424	1,404	1,370	1,308	1,216	1,079	871	509
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[1]	95.10%
Accident Year 2010
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 1,676	1,690	1,698	1,698	1,710	1,690	1,705	1,710	1,724
Total IBNR Plus Expected Development on Reported Claims		$ 54
Cumulative Number of Reported Claims | claim		216,568
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 1,595	1,580	1,562	1,536	1,485	1,387	1,220	1,005	576
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[1]	95.20%
Accident Year 2011
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 1,843	1,859	1,866	1,861	1,871	1,849	1,848	1,840
Total IBNR Plus Expected Development on Reported Claims		$ 67
Cumulative Number of Reported Claims | claim		209,098
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 1,734	1,711	1,682	1,629	1,534	1,389	1,181	609
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[1]	94.10%
Accident Year 2012
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 1,906	1,941	1,955	1,947	1,946	1,952	1,970
Total IBNR Plus Expected Development on Reported Claims		$ 89
Cumulative Number of Reported Claims | claim		218,585
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 1,785	1,735	1,675	1,579	1,418	1,214	824
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[1]	93.70%
Accident Year 2013
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 1,982	2,000	1,996	2,000	2,011	2,036
Total IBNR Plus Expected Development on Reported Claims		$ 128
Cumulative Number of Reported Claims | claim		221,362
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 1,774	1,714	1,617	1,443	1,214	697
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[1]	89.50%
Accident Year 2014
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 2,004	2,038	2,040	2,050	2,083
Total IBNR Plus Expected Development on Reported Claims		$ 186
Cumulative Number of Reported Claims | claim		220,164
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 1,705	1,588	1,422	1,174	594
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[1]	85.10%
Accident Year 2015
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 2,038	2,041	2,047	2,114
Total IBNR Plus Expected Development on Reported Claims		$ 245
Cumulative Number of Reported Claims | claim		227,435
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 1,592	1,404	1,129	619
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[1]	78.10%
Accident Year 2016
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 2,082	2,083	2,117
Total IBNR Plus Expected Development on Reported Claims		$ 432
Cumulative Number of Reported Claims | claim		220,481
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 1,350	1,099	577
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[1]	64.80%
Accident Year 2017
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 2,348	2,375
Total IBNR Plus Expected Development on Reported Claims		$ 737
Cumulative Number of Reported Claims | claim		240,542
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 1,250	709
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[1]	53.20%
Accident Year 2018
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 2,507
Total IBNR Plus Expected Development on Reported Claims		$ 1,123
Cumulative Number of Reported Claims | claim		205,419
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 730
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[1]	29.10%
Excludes short-duration insurance contracts detail for accident years not separately presented
Claims Development [Line Items]
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE)		$ 4,945
Property and transportation
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		7,957
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		6,863
Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE)		23
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE)		1,117
Property and transportation | Accident Year 2009
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		490	491	491	491	494	494	498	505	487	503
Total IBNR Plus Expected Development on Reported Claims		$ 2
Cumulative Number of Reported Claims | claim		138,248
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 485	484	481	480	476	462	440	397	333	219
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[2]	99.00%
Property and transportation | Accident Year 2010
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 657	659	661	657	656	654	646	640	680
Total IBNR Plus Expected Development on Reported Claims		$ 3
Cumulative Number of Reported Claims | claim		138,235
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 650	648	643	638	627	597	536	487	316
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[2]	98.90%
Property and transportation | Accident Year 2011
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 850	853	856	844	833	819	803	816
Total IBNR Plus Expected Development on Reported Claims		$ 6
Cumulative Number of Reported Claims | claim		139,345
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 839	836	828	810	777	732	670	367
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[2]	98.70%
Property and transportation | Accident Year 2012
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 897	900	905	892	880	866	875
Total IBNR Plus Expected Development on Reported Claims		$ 13
Cumulative Number of Reported Claims | claim		145,636
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 892	866	852	826	780	715	574
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[2]	99.40%
Property and transportation | Accident Year 2013
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 890	890	890	884	881	894
Total IBNR Plus Expected Development on Reported Claims		$ 18
Cumulative Number of Reported Claims | claim		141,293
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 859	843	814	769	710	440
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[2]	96.50%
Property and transportation | Accident Year 2014
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 831	834	831	842	856
Total IBNR Plus Expected Development on Reported Claims		$ 25
Cumulative Number of Reported Claims | claim		136,259
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 784	756	702	638	332
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[2]	94.30%
Property and transportation | Accident Year 2015
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 789	789	794	831
Total IBNR Plus Expected Development on Reported Claims		$ 36
Cumulative Number of Reported Claims | claim		134,484
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 717	675	587	361
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[2]	90.90%
Property and transportation | Accident Year 2016
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 733	730	762
Total IBNR Plus Expected Development on Reported Claims		$ 74
Cumulative Number of Reported Claims | claim		122,623
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 590	528	296
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[2]	80.50%
Property and transportation | Accident Year 2017
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 868	904
Total IBNR Plus Expected Development on Reported Claims		$ 128
Cumulative Number of Reported Claims | claim		140,963
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 648	383
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[2]	74.70%
Property and transportation | Accident Year 2018
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 952
Total IBNR Plus Expected Development on Reported Claims		$ 277
Cumulative Number of Reported Claims | claim		119,817
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 399
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[2]	41.90%
Property and transportation | Excludes short-duration insurance contracts detail for accident years not separately presented
Claims Development [Line Items]
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE)		$ 1,094
Specialty casualty
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		9,776
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		6,369
Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE)		477
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE)		3,884
Specialty casualty | Accident Year 2009
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		811	820	824	829	828	833	844	864	887	888
Total IBNR Plus Expected Development on Reported Claims		$ 34
Cumulative Number of Reported Claims | claim		56,985
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 748	740	731	715	691	653	591	510	381	170
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[3]	92.20%
Specialty casualty | Accident Year 2010
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 853	864	867	868	879	865	887	886	870
Total IBNR Plus Expected Development on Reported Claims		$ 47
Cumulative Number of Reported Claims | claim		56,411
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 782	770	756	735	699	644	559	411	191
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[3]	91.70%
Specialty casualty | Accident Year 2011
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 811	819	822	827	842	833	845	847
Total IBNR Plus Expected Development on Reported Claims		$ 52
Cumulative Number of Reported Claims | claim		53,385
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 725	707	687	655	606	517	380	172
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[3]	89.40%
Specialty casualty | Accident Year 2012
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 838	867	872	876	876	883	890
Total IBNR Plus Expected Development on Reported Claims		$ 64
Cumulative Number of Reported Claims | claim		51,885
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 735	713	674	611	508	378	171
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[3]	87.70%
Specialty casualty | Accident Year 2013
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 913	933	928	933	938	956
Total IBNR Plus Expected Development on Reported Claims		$ 99
Cumulative Number of Reported Claims | claim		51,620
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 754	717	656	545	388	180
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[3]	82.60%
Specialty casualty | Accident Year 2014
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 966	992	994	994	1,023
Total IBNR Plus Expected Development on Reported Claims		$ 139
Cumulative Number of Reported Claims | claim		54,494
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 741	668	565	406	187
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[3]	76.70%
Specialty casualty | Accident Year 2015
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 1,030	1,031	1,033	1,068
Total IBNR Plus Expected Development on Reported Claims		$ 185
Cumulative Number of Reported Claims | claim		55,468
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 692	569	406	176
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[3]	67.20%
Specialty casualty | Accident Year 2016
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 1,097	1,108	1,115
Total IBNR Plus Expected Development on Reported Claims		$ 313
Cumulative Number of Reported Claims | claim		53,038
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 571	411	184
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[3]	52.10%
Specialty casualty | Accident Year 2017
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 1,200	1,196
Total IBNR Plus Expected Development on Reported Claims		$ 539
Cumulative Number of Reported Claims | claim		52,658
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 414	196
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[3]	34.50%
Specialty casualty | Accident Year 2018
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 1,257
Total IBNR Plus Expected Development on Reported Claims		$ 705
Cumulative Number of Reported Claims | claim		48,996
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 207
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[3]	16.50%
Specialty casualty | Excludes short-duration insurance contracts detail for accident years not separately presented
Claims Development [Line Items]
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE)		$ 3,407
Specialty financial
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		1,623
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		1,397
Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE)		(1)
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE)		225
Specialty financial | Accident Year 2009
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		186	185	186	187	186	188	184	186	192	192
Total IBNR Plus Expected Development on Reported Claims		$ 1
Cumulative Number of Reported Claims | claim		27,431
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 185	186	186	185	181	171	166	157	145	112
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[4]	99.50%
Specialty financial | Accident Year 2010
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 126	127	130	133	135	132	132	145	138
Total IBNR Plus Expected Development on Reported Claims		$ 1
Cumulative Number of Reported Claims | claim		21,922
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 126	126	128	130	132	122	104	93	61
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[4]	100.00%
Specialty financial | Accident Year 2011
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 139	143	144	147	153	155	157	138
Total IBNR Plus Expected Development on Reported Claims		$ 6
Cumulative Number of Reported Claims | claim		16,368
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 132	131	131	130	123	115	111	58
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[4]	95.00%
Specialty financial | Accident Year 2012
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 132	135	137	139	151	163	163
Total IBNR Plus Expected Development on Reported Claims		$ 6
Cumulative Number of Reported Claims | claim		21,064
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 128	126	121	117	109	104	71
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[4]	97.00%
Specialty financial | Accident Year 2013
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 126	127	131	137	145	140
Total IBNR Plus Expected Development on Reported Claims		$ 9
Cumulative Number of Reported Claims | claim		28,449
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 117	117	113	107	100	70
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[4]	92.90%
Specialty financial | Accident Year 2014
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 147	153	156	157	146
Total IBNR Plus Expected Development on Reported Claims		$ 9
Cumulative Number of Reported Claims | claim		29,411
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 137	128	125	109	62
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[4]	93.20%
Specialty financial | Accident Year 2015
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 153	158	160	156
Total IBNR Plus Expected Development on Reported Claims		$ 16
Cumulative Number of Reported Claims | claim		37,483
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 133	129	110	72
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[4]	86.90%
Specialty financial | Accident Year 2016
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 187	184	179
Total IBNR Plus Expected Development on Reported Claims		$ 24
Cumulative Number of Reported Claims | claim		44,820
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 158	141	88
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[4]	84.50%
Specialty financial | Accident Year 2017
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 215	212
Total IBNR Plus Expected Development on Reported Claims		$ 34
Cumulative Number of Reported Claims | claim		46,921
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 169	120
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[4]	78.60%
Specialty financial | Accident Year 2018
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 212
Total IBNR Plus Expected Development on Reported Claims		$ 79
Cumulative Number of Reported Claims | claim		36,606
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 112
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[4]	52.80%
Specialty financial | Excludes short-duration insurance contracts detail for accident years not separately presented
Claims Development [Line Items]
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE)		$ 226
Other specialty
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		549
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		331
Unpaid losses and LAE — 11th year and prior (excluding unallocated LAE)		62
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE)		280
Other specialty | Accident Year 2009
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		32	33	38	36	37	37	40	41	41	41
Total IBNR Plus Expected Development on Reported Claims		$ 6
Cumulative Number of Reported Claims | claim	[5]	0
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 27	25	26	24	22	22	19	15	12	$ 8
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[6]	84.40%
Other specialty | Accident Year 2010
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 40	40	40	40	40	39	40	39	36
Total IBNR Plus Expected Development on Reported Claims		$ 3
Cumulative Number of Reported Claims | claim	[5]	0
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 37	36	35	33	27	24	21	14	$ 8
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[6]	92.50%
Other specialty | Accident Year 2011
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 43	44	44	43	43	42	43	39
Total IBNR Plus Expected Development on Reported Claims		$ 3
Cumulative Number of Reported Claims | claim	[5]	0
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 38	37	36	34	28	25	20	$ 12
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[6]	88.40%
Other specialty | Accident Year 2012
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 39	39	41	40	39	40	42
Total IBNR Plus Expected Development on Reported Claims		$ 6
Cumulative Number of Reported Claims | claim	[5]	0
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 30	30	28	25	21	17	$ 8
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[6]	76.90%
Other specialty | Accident Year 2013
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 53	50	47	46	47	46
Total IBNR Plus Expected Development on Reported Claims		$ 2
Cumulative Number of Reported Claims | claim	[5]	0
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 44	37	34	22	16	$ 7
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[6]	83.00%
Other specialty | Accident Year 2014
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 60	59	59	57	58
Total IBNR Plus Expected Development on Reported Claims		$ 13
Cumulative Number of Reported Claims | claim	[5]	0
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 43	36	30	21	$ 13
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[6]	71.70%
Other specialty | Accident Year 2015
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 66	63	60	59
Total IBNR Plus Expected Development on Reported Claims		$ 8
Cumulative Number of Reported Claims | claim	[5]	0
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 50	31	26	$ 10
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[6]	75.80%
Other specialty | Accident Year 2016
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 65	61	61
Total IBNR Plus Expected Development on Reported Claims		$ 21
Cumulative Number of Reported Claims | claim	[5]	0
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 31	19	$ 9
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[6]	47.70%
Other specialty | Accident Year 2017
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 65	63
Total IBNR Plus Expected Development on Reported Claims		$ 36
Cumulative Number of Reported Claims | claim	[5]	0
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 19	$ 10
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[6]	29.20%
Other specialty | Accident Year 2018
Claims Development [Line Items]
Incurred Claims and Allocated LAE, Net of Reinsurance		$ 86
Total IBNR Plus Expected Development on Reported Claims		$ 62
Cumulative Number of Reported Claims | claim	[5]	0
Cumulative Paid Claims and Allocated LAE, Net of Reinsurance		$ 12
Cumulative Percentage Paid of Incurred Claims and Allocated LAE, Net of Reinsurance	[6]	14.00%
Other specialty | Excludes short-duration insurance contracts detail for accident years not separately presented
Claims Development [Line Items]
Unpaid losses and LAE, net of reinsurance (excluding unallocated LAE)		$ 218
[1]	Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018).
[2]	Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018).
[3]	Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018).
[4]	Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018).
[5]	The amounts shown in Other specialty represent business assumed by AFG’s internal reinsurance program from the operations that make up AFG’s other Specialty property and casualty insurance sub-segments. Accordingly, the liability for incurred claims and allocated LAE represents additional reserves held on claims counted in the tables provided for the other sub-segments (above).
[6]	Represents the cumulative percentage paid of incurred claims and allocated LAE (net of reinsurance, as estimated at December 31, 2018).

Insurance - Short-duration in_2

Insurance - Short-duration insurance contracts, historical claims duration (Details) - Property and casualty insurance	Dec. 31, 2018
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance [Line Items]
Year 1	32.60%
Year 2	25.50%
Year 3	12.20%
Year 4	8.80%
Year 5	5.50%
Year 6	3.20%
Year 7	2.00%
Year 8	1.20%
Year 9	0.80%
Year 10	0.70%
Year 1, Cumulative	32.60%
Year 2, Cumulative	58.10%
Year 3, Cumulative	70.30%
Year 4, Cumulative	79.10%
Year 5, Cumulative	84.60%
Year 6, Cumulative	87.80%
Year 7, Cumulative	89.80%
Year 8, Cumulative	91.00%
Year 9, Cumulative	91.80%
Year 10, Cumulative	92.50%
Property and transportation
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance [Line Items]
Year 1	46.20%
Year 2	28.70%
Year 3	8.60%
Year 4	6.50%
Year 5	3.70%
Year 6	2.00%
Year 7	1.40%
Year 8	0.40%
Year 9	0.50%
Year 10	0.20%
Year 1, Cumulative	46.20%
Year 2, Cumulative	74.90%
Year 3, Cumulative	83.50%
Year 4, Cumulative	90.00%
Year 5, Cumulative	93.70%
Year 6, Cumulative	95.70%
Year 7, Cumulative	97.10%
Year 8, Cumulative	97.50%
Year 9, Cumulative	98.00%
Year 10, Cumulative	98.20%
Specialty casualty
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance [Line Items]
Year 1	19.10%
Year 2	23.20%
Year 3	16.20%
Year 4	11.10%
Year 5	7.00%
Year 6	4.30%
Year 7	2.60%
Year 8	1.90%
Year 9	1.30%
Year 10	1.00%
Year 1, Cumulative	19.10%
Year 2, Cumulative	42.30%
Year 3, Cumulative	58.50%
Year 4, Cumulative	69.60%
Year 5, Cumulative	76.60%
Year 6, Cumulative	80.90%
Year 7, Cumulative	83.50%
Year 8, Cumulative	85.40%
Year 9, Cumulative	86.70%
Year 10, Cumulative	87.70%
Specialty financial
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance [Line Items]
Year 1	50.50%
Year 2	26.40%
Year 3	7.50%
Year 4	5.80%
Year 5	4.70%
Year 6	1.70%
Year 7	0.50%
Year 8	(0.10%)
Year 9	0.00%
Year 10	(0.50%)
Year 1, Cumulative	50.50%
Year 2, Cumulative	76.90%
Year 3, Cumulative	84.40%
Year 4, Cumulative	90.20%
Year 5, Cumulative	94.90%
Year 6, Cumulative	96.60%
Year 7, Cumulative	97.10%
Year 8, Cumulative	97.00%
Year 9, Cumulative	97.00%
Year 10, Cumulative	96.50%
Other specialty
Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance [Line Items]
Year 1	18.70%
Year 2	17.00%
Year 3	12.60%
Year 4	14.10%
Year 5	9.30%
Year 6	7.60%
Year 7	3.40%
Year 8	3.70%
Year 9	(0.30%)
Year 10	6.30%
Year 1, Cumulative	18.70%
Year 2, Cumulative	35.70%
Year 3, Cumulative	48.30%
Year 4, Cumulative	62.40%
Year 5, Cumulative	71.70%
Year 6, Cumulative	79.30%
Year 7, Cumulative	82.70%
Year 8, Cumulative	86.40%
Year 9, Cumulative	86.10%
Year 10, Cumulative	92.40%

Insurance - Net earnings and ca

Insurance - Net earnings and capital and surplus on a statutory basis for the insurance subsidiaries (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property and casualty companies
Statutory information
Net Earnings	$ 546	$ 484	$ 461
Capital and Surplus	2,867	2,729
Life insurance companies
Statutory information
Net Earnings	802	286	$ 167
Capital and Surplus	$ 2,701	$ 2,132

Insurance - Reinsurance informa

Insurance - Reinsurance information table including assumed, ceded, and recoveries (Details) - Property and casualty insurance - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effects of Reinsurance [Line Items]
Direct premiums written	$ 6,626	$ 6,310	$ 5,858
Reinsurance assumed	214	192	123
Reinsurance ceded	(1,817)	(1,751)	(1,595)
Net written premiums	5,023	4,751	4,386
Direct premiums earned	6,472	6,112	5,745
Reinsurance assumed	204	157	118
Reinsurance ceded	(1,811)	(1,690)	(1,535)
Net earned premiums	4,865	4,579	4,328
Reinsurance recoveries	$ 1,249	$ 1,379	$ 810

Insurance - Liabilities for exc

Insurance - Liabilities for excess benefits expected to be paid on future deaths and annuitizations, guaranteed withdrawal benefits and accrued persistency and premium bonuses (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Insurance [Abstract]
Expected death and annuitization	$ 229	$ 228
Guaranteed withdrawal benefits	472	358
Accrued persistency and premium bonuses	$ 1	$ 3

Additional Information - Narrat

Additional Information - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for reinsurance recoverables [Line Items]
Total rental expense	$ 70	$ 69	$ 67
Operating lease future minimum payments due in next year	65
Operating lease future minimum payments due in year two	57
Operating lease future minimum payments due in year three	50
Operating lease future minimum payments due in year four	40
Operating lease future minimum payments due in year five	35
Operating lease future minimum payments due after year five	79
Commitments to fund limited partnerships	949
Retirement and employee savings plan expense	37	45	43
Allowance for reinsurance recoverables
Allowance for reinsurance recoverables [Line Items]
Aggregate allowance for losses on reinsurance recoverables	18	20
Net expense reduction against the allowance for losses on reinsurance recoverables	(2)
Reinsurance recoverable write-offs	$ 2
Maximum | Allowance for reinsurance recoverables
Allowance for reinsurance recoverables [Line Items]
Net expense reduction against the allowance for losses on reinsurance recoverables		$ (1)	$ (1)

Condensed Financial Informati_2

Condensed Financial Information of Parent Company - Condensed Balance Sheet (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets:
Cash and cash equivalents		$ 1,515	$ 2,338	$ 2,107	$ 1,220
Other investments		267	312
Other assets		1,529	1,504
Total assets		63,456	60,658	55,072
Liabilities and Equity:
Long-term debt		1,302	1,301
Other liabilities		1,774	1,887
Shareholders’ equity		4,970	5,330
Total liabilities and equity		63,456	60,658
AFG
Assets:
Cash and cash equivalents		158	299	$ 197	$ 189
Investment in securities		65	70
Investment in subsidiaries	[1]	6,155	6,310
Other investments		2	2
Other assets		68	141
Total assets		6,448	6,822
Liabilities and Equity:
Long-term debt		1,302	1,301
Other liabilities		176	191
Shareholders’ equity		4,970	5,330
Total liabilities and equity		$ 6,448	$ 6,822
[1]	Investment in subsidiaries includes intercompany receivables and payables.

Condensed Financial Informati_3

Condensed Financial Information of Parent Company - Condensed Statement of Earnings (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Total revenues	$ 1,690	$ 2,008	$ 1,833	$ 1,619	$ 1,808	$ 1,835	$ 1,646	$ 1,576	$ 7,150	$ 6,865	$ 6,498
Costs and Expenses:
Interest charges on other borrowings									62	85	77
Other expenses									353	422	353
Total costs and expenses									6,511	6,141	5,711
Earnings before income taxes									639	724	787
Provision for income taxes									122	247	119
Net Earnings Attributable to Shareholders	$ (29)	$ 204	$ 210	$ 145	166	$ 11	$ 145	$ 153	530	475	649
AFG
Revenues:
Dividends from subsidiaries									261	681	643
Equity in undistributed earnings of subsidiaries									529	264	286
Investment and other income									2	13	7
Total revenues									792	958	936
Costs and Expenses:
Interest charges on intercompany borrowings									8	9	9
Interest charges on other borrowings									62	85	77
Other expenses									70	142	82
Total costs and expenses									140	236	168
Earnings before income taxes									652	722	768
Provision for income taxes					$ (56)				122	247	119
Net Earnings Attributable to Shareholders									$ 530	$ 475	$ 649

Condensed Financial Informati_4

Condensed Financial Information of Parent Company - Condensed Statement of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Other Comprehensive Income [Abstract]
Net earnings (losses) attributable to shareholders	$ (29)	$ 204	$ 210	$ 145	$ 166	$ 11	$ 145	$ 153	$ 530	$ 475	$ 649
Comprehensive income (loss) attributable to shareholders									(14)	771	711
AFG
Statement of Other Comprehensive Income [Abstract]
Net earnings (losses) attributable to shareholders									530	475	649
Other comprehensive income (loss), net of tax									(544)	296	62
Comprehensive income (loss) attributable to shareholders									$ (14)	$ 771	$ 711

Condensed Financial Informati_5

Condensed Financial Information of Parent Company - Condensed Statement of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities:
Net earnings (losses) attributable to shareholders	$ (29)	$ 204	$ 210	$ 145	$ 166	$ 11	$ 145	$ 153	$ 530	$ 475	$ 649
Adjustments:
Net cash provided by operating activities									2,083	1,804	1,150
Investing Activities:
Payments for (proceeds from) other investing activities									30	2	(83)
Net cash used in investing activities									(5,350)	(3,292)	(2,981)
Financing Activities:
Additional long-term borrowings									0	712	302
Reductions of long-term debt									0	(745)	(18)
Issuances of Common Stock									33	37	35
Repurchases of Common Stock									(6)	0	(133)
Cash dividends paid on Common Stock									(394)	(417)	(185)
Proceeds from (payments for) other financing activities									0	(4)	(13)
Net cash provided by (used in) financing activities									2,444	1,719	2,718
Net Change in Cash and Cash Equivalents									(823)	231	887
Cash and cash equivalents at beginning of year				2,338				2,107	2,338	2,107	1,220
Cash and cash equivalents at end of year	1,515				2,338				1,515	2,338	2,107
AFG
Operating Activities:
Net earnings (losses) attributable to shareholders									530	475	649
Adjustments:
Equity in net earnings of subsidiaries									(637)	(575)	(638)
Dividends from subsidiaries									238	580	611
Other operating activities, net									84	98	(67)
Net cash provided by operating activities									215	578	555
Investing Activities:
Capital contributions to subsidiaries									(11)	(93)	(560)
Returns of capital from subsidiaries									23	30	0
Purchases of investments, property and equipment									(5)	(2)	(1)
Proceeds from maturities and redemptions of investments									3	2	1
Net cash used in investing activities									10	(63)	(560)
Financing Activities:
Additional long-term borrowings									0	712	296
Reductions of long-term debt									0	(745)	0
Issuances of Common Stock									34	37	35
Repurchases of Common Stock									(6)	0	(133)
Cash dividends paid on Common Stock									(394)	(417)	(185)
Net cash provided by (used in) financing activities									(366)	(413)	13
Net Change in Cash and Cash Equivalents									(141)	102	8
Cash and cash equivalents at beginning of year				$ 299				$ 197	299	197	189
Cash and cash equivalents at end of year	$ 158				$ 299				$ 158	$ 299	$ 197

Supplementary Insurance Infor_2

Supplementary Insurance Information - Table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred policy acquisition costs	$ 1,682	$ 1,216	$ 1,239
Reserves for future policy benefits, claims and unpaid losses and LAE	46,992	43,652	39,161
Unearned premiums	2,595	2,410	2,171
Net earned premiums	4,889	4,601	4,352
Net investment income	2,094	1,831	1,696
Benefits, claims, losses and settlement expenses	4,041	3,873	3,595
Amortization of deferred policy acquisition costs	860	690	673
Other operating expenses	1,610	1,578	1,443
Net written premiums (excluding life)	5,026	4,754	4,389
Property and casualty insurance
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred policy acquisition costs	299	270	238
Reserves for future policy benefits, claims and unpaid losses and LAE	9,741	9,678	8,563
Unearned premiums	2,595	2,410	2,171
Net earned premiums	4,865	4,579	4,328
Net investment income	438	362	350
Benefits, claims, losses and settlement expenses	3,003	2,955	2,762
Amortization of deferred policy acquisition costs	644	556	520
Other operating expenses	957	867	870
Net written premiums (excluding life)	5,023	4,751	4,386
Annuity
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred policy acquisition costs	1,360	920	981
Reserves for future policy benefits, claims and unpaid losses and LAE	36,616	33,316	29,907
Net investment income	1,638	1,458	1,356
Benefits, claims, losses and settlement expenses	998	892	800
Amortization of deferred policy acquisition costs	212	130	149
Other operating expenses	174	159	142
Other
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Line Items]
Deferred policy acquisition costs	23	26	20
Reserves for future policy benefits, claims and unpaid losses and LAE	635	658	691
Net earned premiums	24	22	24
Net investment income	18	11	(10)
Benefits, claims, losses and settlement expenses	40	26	33
Amortization of deferred policy acquisition costs	4	4	4
Other operating expenses	479	552	431
Net written premiums (excluding life)	$ 3	$ 3	$ 3