v3.26.1
INVESTMENTS - Additional Information (Detail)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
investment
Jun. 30, 2025
USD ($)
investment
Mar. 31, 2026
USD ($)
Dec. 31, 2025
USD ($)
Mar. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Schedule of Investments [Line Items]                
Held to maturity securities transferred to available for sale securities, number of investments | investment     0 0        
Real estate owned, impairment losses   $ 6 $ 24 $ 6        
Real estate owned, estimated fair value after impairment $ 179 12 179 12        
Equity securities, FV-NI, unrealized gain (loss) 60 101 29 47        
Transitional real estate loan commitments 125   125          
Middle market loan commitments 696   696          
Other loan commitments 83   83          
Nonaccrual loans, interest income 1   7 1        
Financing receivables, commitments to lend 0   0     $ 15    
Allowance for credit losses 533   533     426    
Fixed maturity securities, held-to-maturity, amortized cost 15,509   15,509     16,125    
Real estate owned, accumulated depreciation 53   53     41    
Limited partnerships investment commitments 2,800   2,800     3,000    
Securities lending, securities received as collateral 0   0     2,200    
Repurchase agreements and repurchase-to-maturity transactions outstanding 0   0     0    
Variable Interest Entity, Not Consolidated                
Schedule of Investments [Line Items]                
Limited partnerships investment commitments 2,200   2,200     2,100    
Variable Interest Entity, Consolidated                
Schedule of Investments [Line Items]                
Restricted cash and cash equivalents 63   63          
Variable Interest Entity, Consolidated | Aflac Re Bermuda Ltd. (Aflac Re)                
Schedule of Investments [Line Items]                
Debt Securities, Available-for-Sale, Restricted 618   618          
Restricted cash and cash equivalents 6   6          
Real estate owned                
Schedule of Investments [Line Items]                
Real estate owned, depreciation expense 8 8 15 14        
Transitional real estate loans                
Schedule of Investments [Line Items]                
Nonaccrual loans, no allowance 168   168     30    
Allowance for credit losses 315 243 315 243 $ 286 277 $ 203 $ 199
Transitional real estate loans | Potential Foreclosure or Deed-in-lieu Foreclosure                
Schedule of Investments [Line Items]                
Loans in anticipation of potential foreclosure or deed in lieu of foreclosure 139   139          
Allowance for credit losses 86   86          
Middle market loans                
Schedule of Investments [Line Items]                
Nonaccrual loans, no allowance 0   0     36    
Allowance for credit losses 209 $ 127 209 $ 127 $ 163 $ 138 $ 150 $ 140
Zero-credit-loss expectation | Japan government and agencies                
Schedule of Investments [Line Items]                
Fixed maturity securities, held-to-maturity, amortized cost $ 14,800   $ 14,800          
California | Geographic Concentration Risk | Mortgages                
Schedule of Investments [Line Items]                
Concentration Risk, Percentage     20.00%          
Texas | Geographic Concentration Risk | Mortgages                
Schedule of Investments [Line Items]                
Concentration Risk, Percentage     14.00%          
Arizona | Geographic Concentration Risk | Mortgages                
Schedule of Investments [Line Items]                
Concentration Risk, Percentage     7.00%