STATUTORY ACCOUNTING AND DIVIDEND RESTRICTIONS - Capital and Surplus Based on Statutory Accounting Practices (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Aflac
Statutory Accounting Practices [Line Items]
Capital and surplus, NAIC basis	$ 2,627	$ 2,088
CAIC
Statutory Accounting Practices [Line Items]
Capital and surplus, NAIC basis	244	271
TOIC
Statutory Accounting Practices [Line Items]
Capital and surplus, NAIC basis	57	61
Aflac New York
Statutory Accounting Practices [Line Items]
Capital and surplus, NAIC basis	$ 360	$ 352