v3.26.1
POLICY LIABILITIES - Summary of Net Earned Premiums Recognized (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Liability for Future Policy Benefit, Activity [Line Items]    
Reinsurance ceded $ (135) $ (88)
Net earned premiums [1] 3,310 3,381
Aflac Japan | Cancer    
Liability for Future Policy Benefit, Activity [Line Items]    
Gross premiums 816 839
Aflac Japan | Medical and other health    
Liability for Future Policy Benefit, Activity [Line Items]    
Gross premiums 495 529
Aflac Japan | Life insurance    
Liability for Future Policy Benefit, Activity [Line Items]    
Gross premiums 298 316
Aflac Japan | Other    
Liability for Future Policy Benefit, Activity [Line Items]    
Gross premiums 29 32
Aflac U.S. | Life insurance    
Liability for Future Policy Benefit, Activity [Line Items]    
Gross premiums 198 169
Aflac U.S. | Accident    
Liability for Future Policy Benefit, Activity [Line Items]    
Gross premiums 305 311
Aflac U.S. | Disability    
Liability for Future Policy Benefit, Activity [Line Items]    
Gross premiums 374 352
Aflac U.S. | Critical care    
Liability for Future Policy Benefit, Activity [Line Items]    
Gross premiums 444 441
Aflac U.S. | Hospital indemnity    
Liability for Future Policy Benefit, Activity [Line Items]    
Gross premiums 183 184
Aflac U.S. | Dental/vision    
Liability for Future Policy Benefit, Activity [Line Items]    
Gross premiums 58 49
Aflac U.S. | Other    
Liability for Future Policy Benefit, Activity [Line Items]    
Gross premiums 63 49
Corporate and other    
Liability for Future Policy Benefit, Activity [Line Items]    
Gross premiums $ 182 $ 198
[1] Includes a gain (loss) of an immaterial amount for the three-month periods ended March 31, 2026 and 2025, respectively, related to remeasurement of the deferred profit liability for limited-payment contracts.