v3.26.1
DEFERRED POLICY ACQUISITION COSTS - Schedule Of Deferred Policy Acquisition Costs (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Deferred Policy Acquisition Cost [Line Items]      
Balance, beginning of period $ 9,034 $ 8,758 $ 8,758
Capitalization 272   1,105
Amortization expense (221) (216) (874)
Foreign currency translation and other (109)   45
Balance, end of period 8,976   9,034
Aflac Japan | Cancer      
Deferred Policy Acquisition Cost [Line Items]      
Balance, beginning of period 2,965 2,776 2,776
Capitalization 80   357
Amortization expense (46)   (188)
Foreign currency translation and other (62)   20
Balance, end of period 2,937   2,965
Aflac Japan | Medical and other health      
Deferred Policy Acquisition Cost [Line Items]      
Balance, beginning of period 1,840 1,833 1,833
Capitalization 26   85
Amortization expense (23)   (99)
Foreign currency translation and other (38)   21
Balance, end of period 1,805   1,840
Aflac Japan | Life insurance      
Deferred Policy Acquisition Cost [Line Items]      
Balance, beginning of period 446 441 441
Capitalization 14   33
Amortization expense (8)   (33)
Foreign currency translation and other (9)   5
Balance, end of period 443   446
Aflac Japan | Other      
Deferred Policy Acquisition Cost [Line Items]      
Balance, beginning of period 51 52 52
Capitalization 0   3
Amortization expense (1)   (3)
Foreign currency translation and other 0   (1)
Balance, end of period 50   51
Aflac U.S. | Life insurance      
Deferred Policy Acquisition Cost [Line Items]      
Balance, beginning of period 277 219 219
Capitalization 29   98
Amortization expense (11)   (40)
Foreign currency translation and other 0   0
Balance, end of period 295   277
Aflac U.S. | Accident      
Deferred Policy Acquisition Cost [Line Items]      
Balance, beginning of period 909 915 915
Capitalization 32   137
Amortization expense (37)   (143)
Foreign currency translation and other 0   0
Balance, end of period 904   909
Aflac U.S. | Disability      
Deferred Policy Acquisition Cost [Line Items]      
Balance, beginning of period 641 636 636
Capitalization 30   127
Amortization expense (31)   (122)
Foreign currency translation and other 0   0
Balance, end of period 640   641
Aflac U.S. | Critical care      
Deferred Policy Acquisition Cost [Line Items]      
Balance, beginning of period 1,355 1,348 1,348
Capitalization 37   162
Amortization expense (40)   (155)
Foreign currency translation and other 0   0
Balance, end of period 1,352   1,355
Aflac U.S. | Hospital indemnity      
Deferred Policy Acquisition Cost [Line Items]      
Balance, beginning of period 463 452 452
Capitalization 21   90
Amortization expense (21)   (79)
Foreign currency translation and other 0   0
Balance, end of period 463   463
Aflac U.S. | Dental/vision      
Deferred Policy Acquisition Cost [Line Items]      
Balance, beginning of period 87 86 86
Capitalization 3   13
Amortization expense (3)   (12)
Foreign currency translation and other 0   0
Balance, end of period 87   87
Aflac U.S. | Other      
Deferred Policy Acquisition Cost [Line Items]      
Balance, beginning of period 0 $ 0 0
Capitalization 0   0
Amortization expense 0   0
Foreign currency translation and other 0   0
Balance, end of period $ 0   $ 0