POLICY LIABILITIES - Schedule of Changes in Other Policyholders' Funds (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023
Policyholder Account Balance [Line Items]
Other deposit type reserves		$ 239	$ 230
Total		5,460	6,169
Aflac Japan
Policyholder Account Balance [Line Items]
Total		5,460	6,169
Aflac Japan | Fixed Annuity
Policyholder Account Balance [Line Items]
Beginning balance	[1]	5,939	6,423
Premiums received	[1]	104	126
Transfers from WAYS conversions	[1]	249	229
Surrenders and withdrawals	[1]	(58)	(59)
Benefit payments	[1]	(446)	(419)
Interest credited	[1]	49	53
Foreign currency translation and other	[1]	(616)	(414)
Ending balance	[1]	$ 5,221	$ 5,939

[1] Aflac Japan fixed annuities