Investments - Components of the net unrealized gain on securities that is included in AOCI in the Balance Sheet (Details) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Unrealized gain on:
Pretax		$ 622	$ 517
Deferred Tax and Amounts Attributable to Noncontrolling Interests		(218)	(185)
Net		404	332
Total investments
Unrealized gain on:
Pretax		960	803
Deferred Tax and Amounts Attributable to Noncontrolling Interests		(336)	(285)
Net		624	518
Total fixed maturities
Unrealized gain on:
Pretax		809	719
Deferred Tax and Amounts Attributable to Noncontrolling Interests		(283)	(255)
Net		526	464
Fixed maturities — annuity segment
Unrealized gain on:
Pretax	[1]	640	523
Deferred Tax and Amounts Attributable to Noncontrolling Interests	[1]	(224)	(183)
Net	[1]	416	340
Fixed maturities — all other
Unrealized gain on:
Pretax		169	196
Deferred Tax and Amounts Attributable to Noncontrolling Interests		(59)	(72)
Net		110	124
Equity securities
Unrealized gain on:
Pretax		151	84
Deferred Tax and Amounts Attributable to Noncontrolling Interests		(53)	(30)
Net		98	54
Deferred policy acquisition costs — annuity segment
Unrealized gain on:
Pretax		(273)	(233)
Deferred Tax and Amounts Attributable to Noncontrolling Interests		96	82
Net		(177)	(151)
Annuity benefits accumulated
Unrealized gain on:
Pretax		(78)	(64)
Deferred Tax and Amounts Attributable to Noncontrolling Interests		27	22
Net		(51)	(42)
Unearned revenue
Unrealized gain on:
Pretax		13	11
Deferred Tax and Amounts Attributable to Noncontrolling Interests		(5)	(4)
Net		$ 8	$ 7

[1] Net unrealized gains on fixed maturity investments supporting AFG’s annuity benefits accumulated.