REINSURANCE - Effect of Reinsurance on Premiums and Benefits and Claims (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Effects of Reinsurance [Line Items]
Direct premium income	$ 3,877	$ 4,490	$ 8,091	$ 9,141
Net earned premiums	3,849	4,441	8,028	9,034
Direct benefits and claims	2,319	2,687	4,824	5,463
Benefits and claims, net	2,298	2,653	4,785	5,387
Intercompany eliminations
Effects of Reinsurance [Line Items]
Ceded benefits and claims	6	8	12	16
Assumed benefits and claims from other companies	(6)	(8)	(12)	(16)
All other
Effects of Reinsurance [Line Items]
Ceded premiums	(17)	(15)	(36)	(34)
Assumed premiums earned	40	30	81	57
Ceded benefits and claims	(14)	(9)	(18)	(17)
Assumed benefits and claims from other companies	40	27	79	50
Aflac Japan
Effects of Reinsurance [Line Items]
Net earned premiums	2,419	2,987	5,143	6,111
Aflac Japan \| Closed Block
Effects of Reinsurance [Line Items]
Ceded premiums	(87)	(109)	(185)	(223)
Assumed premiums earned	36	45	77	93
Ceded benefits and claims	(82)	(94)	(173)	(193)
Assumed benefits and claims from other companies	$ 35	$ 42	$ 73	$ 84

Amount of earned premiums assumed from other entities.

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