REINSURANCE - Effect of Reinsurance on Premiums and Benefits and Claims (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Effects of Reinsurance [Line Items]
Direct premium income	$ 3,681	$ 4,426	$ 11,772	$ 13,567
Net earned premiums	3,651	4,372	11,679	13,406
Direct benefits and claims	2,385	2,649	7,209	8,112
Benefits and claims, net	2,340	2,609	7,125	7,996
Intercompany eliminations
Effects of Reinsurance [Line Items]
Ceded benefits and claims	5	8	17	24
Assumed benefits and claims from other companies	(5)	(8)	(17)	(24)
All other
Effects of Reinsurance [Line Items]
Ceded premiums	(20)	(19)	(55)	(54)
Assumed premiums earned	35	27	116	84
Ceded benefits and claims	(9)	(9)	(28)	(25)
Assumed benefits and claims from other companies	24	21	105	71
Aflac Japan
Effects of Reinsurance [Line Items]
Net earned premiums	2,241	2,934	7,384	9,045
Aflac Japan \| Closed Block
Effects of Reinsurance [Line Items]
Ceded premiums	(80)	(107)	(266)	(329)
Assumed premiums earned	35	45	112	138
Ceded benefits and claims	(103)	(94)	(276)	(288)
Assumed benefits and claims from other companies	$ 43	$ 42	$ 115	$ 126

Amount of earned premiums assumed from other entities.

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