Investments - Components of the net unrealized gain on securities that is included in AOCI in the Balance Sheet (Details) - USD ($) $ in Millions		Sep. 30, 2016	Dec. 31, 2015
Unrealized gain on:
Pretax		$ 1,205	$ 517
Deferred Tax and Amounts Attributable to Noncontrolling Interests		(433)	(185)
Net		772	332
Total investments
Unrealized gain on:
Pretax		1,969	803
Deferred Tax and Amounts Attributable to Noncontrolling Interests		(700)	(285)
Net		1,269	518
Total fixed maturities
Unrealized gain on:
Pretax		1,808	719
Deferred Tax and Amounts Attributable to Noncontrolling Interests		(642)	(255)
Net		1,166	464
Fixed maturities — annuity segment
Unrealized gain on:
Pretax	[1]	1,420	523
Deferred Tax and Amounts Attributable to Noncontrolling Interests	[1]	(497)	(183)
Net	[1]	923	340
Fixed maturities — all other
Unrealized gain on:
Pretax		388	196
Deferred Tax and Amounts Attributable to Noncontrolling Interests		(145)	(72)
Net		243	124
Equity securities
Unrealized gain on:
Pretax		161	84
Deferred Tax and Amounts Attributable to Noncontrolling Interests		(58)	(30)
Net		103	54
Deferred policy acquisition costs — annuity segment
Unrealized gain on:
Pretax		(614)	(233)
Deferred Tax and Amounts Attributable to Noncontrolling Interests		215	82
Net		(399)	(151)
Annuity benefits accumulated
Unrealized gain on:
Pretax		(179)	(64)
Deferred Tax and Amounts Attributable to Noncontrolling Interests		63	22
Net		(116)	(42)
Life, accident and health reserves
Unrealized gain on:
Pretax		(1)
Deferred Tax and Amounts Attributable to Noncontrolling Interests		0
Net		(1)
Unearned revenue
Unrealized gain on:
Pretax		30	11
Deferred Tax and Amounts Attributable to Noncontrolling Interests		(11)	(4)
Net		$ 19	$ 7

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