SHARE-BASED COMPENSATION - Key Assumptions Used to Value PBRS (Detail) - Performance Based Vesting Condition - Restricted Stock	12 Months Ended
	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility (based on Aflac Inc. and peer group historical daily stock price)	32.30%
Expected life from grant date (years)	2 years 10 months 24 days
Risk-free interest rate (based on U.S. Treasury yields at the date of grant)	4.10%