Investments - Components of the net unrealized gain on securities that is included in AOCI in the Balance Sheet (Details) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018
Unrealized gain on:
Pretax		$ 1,091	$ 105
Deferred Tax		(229)	(22)
Net		862	83
Total fixed maturities
Unrealized gain on:
Pretax		1,981	160
Deferred Tax		(416)	(34)
Net		1,565	126
Fixed maturities — annuity segment
Unrealized gain on:
Pretax	[1]	1,611	101
Deferred Tax	[1]	(338)	(21)
Net	[1]	1,273	80
Fixed maturities — all other
Unrealized gain on:
Pretax		370	59
Deferred Tax		(78)	(13)
Net		292	46
Deferred policy acquisition costs — annuity segment
Unrealized gain on:
Pretax		(681)	(42)
Deferred Tax		143	9
Net		(538)	(33)
Annuity benefits accumulated
Unrealized gain on:
Pretax		(219)	(14)
Deferred Tax		46	3
Net		(173)	(11)
Life, accident and health reserves
Unrealized gain on:
Pretax		(1)
Deferred Tax		0
Net		(1)
Unearned revenue
Unrealized gain on:
Pretax		11	1
Deferred Tax		(2)	0
Net		$ 9	$ 1

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