POLICY LIABILITIES - Schedule of Changes in Other Policyholders' Funds (Details) - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2023	Dec. 31, 2022
Policyholder Account Balance [Line Items]
Other deposit type reserves		$ 232	$ 220
Total		5,884	6,643
Aflac Japan | Fixed Annuity
Policyholder Account Balance [Line Items]
Beginning balance	[1]	6,423	7,410
Premiums received	[1]	90	150
Transfers from WAYS conversions	[1]	162	214
Surrenders and withdrawals	[1]	(40)	(52)
Benefit payments	[1]	(296)	(367)
Interest credited	[1]	37	57
Foreign currency translation and other	[1]	(724)	(989)
Ending balance	[1]	$ 5,652	$ 6,423

[1] Aflac Japan fixed annuities