STATUTORY ACCOUNTING AND DIVIDEND RESTRICTIONS - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Aflac Japan
Statutory Accounting Practices [Line Items]
Capital and surplus, statutory accounting practices of the state or country basis	$ 8,100	$ 6,700
Aflac
Statutory Accounting Practices [Line Items]
Dividends declared	894	594
Amount available for dividend distribution without prior approval from regulatory agency	1,100
Aflac New York
Statutory Accounting Practices [Line Items]
Dividends declared	67	83
Aflac Re Bermuda
Statutory Accounting Practices [Line Items]
Capital and surplus, statutory accounting practices of the state or country basis	439	$ 195
Dividends paid	$ 0