Investments - Components of the net unrealized gain on securities that is included in AOCI in the Balance Sheet (Details) - USD ($) $ in Millions		Mar. 31, 2020	Dec. 31, 2019
Unrealized gain on:
Pretax		$ 20	$ 1,091
Deferred Tax		(4)	(229)
Net		16	862
Total fixed maturities
Unrealized gain on:
Pretax		94	1,981
Deferred Tax		(19)	(416)
Net		75	1,565
Fixed maturities — annuity segment
Unrealized gain on:
Pretax	[1]	124	1,611
Deferred Tax	[1]	(26)	(338)
Net	[1]	98	1,273
Fixed maturities — all other
Unrealized gain on:
Pretax		(30)	370
Deferred Tax		7	(78)
Net		(23)	292
Deferred policy acquisition costs — annuity segment
Unrealized gain on:
Pretax		(57)	(681)
Deferred Tax		12	143
Net		(45)	(538)
Annuity benefits accumulated
Unrealized gain on:
Pretax		(18)	(219)
Deferred Tax		3	46
Net		(15)	(173)
Life, accident and health reserves
Unrealized gain on:
Pretax			(1)
Deferred Tax			0
Net			(1)
Unearned revenue
Unrealized gain on:
Pretax		1	11
Deferred Tax		0	(2)
Net		$ 1	$ 9

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