REINSURANCE Effect of Reinsurance on Premiums and Benefits and Claims (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Effects of Reinsurance [Line Items]
Direct premium income	$ 15,387	$ 17,857	$ 18,955
Ceded premiums	(419)	(504)	(553)
Assumed premiums earned	295	294	220
Net premium income	15,263	17,647	18,622
Direct benefits and claims	9,255	10,716	12,080
Benefits and claims, net	9,153	10,576	11,796
Intercompany eliminations
Effects of Reinsurance [Line Items]
Ceded benefits and claims	23	31	39
Assumed benefits and claims from other companies	(23)	(31)	(39)
All other
Effects of Reinsurance [Line Items]
Ceded premiums	(76)	(73)	(87)
Assumed premiums earned	151	114	25
Ceded benefits and claims	(38)	(36)	(63)
Assumed benefits and claims from other companies	131	110	18
Aflac Japan
Effects of Reinsurance [Line Items]
Net premium income	9,548	11,853	12,670
Benefits and claims, net	6,565	7,963	8,851
Aflac Japan \| Closed block
Effects of Reinsurance [Line Items]
Ceded premiums	(343)	(431)	(466)
Assumed premiums earned	144	180	195
Ceded benefits and claims	(340)	(379)	(419)
Assumed benefits and claims from other companies	$ 145	$ 165	$ 180

Amount of earned premiums assumed from other entities.

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