v3.26.3
INVESTMENTS - Additional Information (Detail)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2026
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2026
USD ($)
investment
Sep. 30, 2025
USD ($)
investment
Jun. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Jun. 30, 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 $ 0 $ 0 $ 24 $ 6        
Real estate owned, estimated fair value after impairment 179 12 179 12        
Equity securities, FV-NI, unrealized gain (loss) 38 11 31 46        
Transitional real estate loan commitments 87   87          
Middle market loan commitments 817   817          
Other loan commitments 93   93          
Nonaccrual loans, interest income 2 0 9 1        
Financing receivables, commitments to lend 2   2     $ 15    
Allowance for credit losses 607   607     426    
Fixed maturity securities, held-to-maturity, amortized cost 16,003   16,003     16,125    
Real estate owned, accumulated depreciation 61   61     41    
Limited partnerships investment commitments 2,800   2,800     3,000    
Securities lending, securities received as collateral 0   0     2,200    
Fixed maturity securities, available-for-sale 60,915   60,915     64,121    
Fixed maturity securities, held-to-maturity 15,999 [1]   15,999 [1]     16,120    
Total borrowings 6,874   6,874     3,989    
Securities lending transactions                
Schedule of Investments [Line Items]                
Fixed maturity securities, available-for-sale 1,200   1,200     1,000    
Fixed maturity securities, held-to-maturity 5,700   5,700     2,900    
Total borrowings 6,634   6,634     3,989    
Repurchase agreements                
Schedule of Investments [Line Items]                
Fixed maturity securities, held-to-maturity 256   256          
Total borrowings 240   240     0    
Variable Interest Entity, Not Consolidated                
Schedule of Investments [Line Items]                
Limited partnerships investment commitments 2,300   2,300     2,100    
Fixed maturity securities, available-for-sale 8,011   8,011     6,750    
Variable Interest Entity, Consolidated                
Schedule of Investments [Line Items]                
Restricted cash and cash equivalents 65   65          
Fixed maturity securities, available-for-sale 3,966   3,966     3,636    
Variable Interest Entity, Consolidated | Aflac Re Bermuda Ltd. (Aflac Re)                
Schedule of Investments [Line Items]                
Debt securities, available-for-sale, restricted 578   578          
Restricted cash and cash equivalents 14   14          
Real estate owned                
Schedule of Investments [Line Items]                
Real estate owned, depreciation expense 8 8 23 21        
Japan government and agencies | Securities lending transactions                
Schedule of Investments [Line Items]                
Total borrowings 5,389   5,389     2,920    
Japan government and agencies | Repurchase agreements                
Schedule of Investments [Line Items]                
Total borrowings 240   240          
Zero-credit-loss expectation | Japan government and agencies                
Schedule of Investments [Line Items]                
Fixed maturity securities, held-to-maturity, amortized cost 15,200   15,200          
Transitional real estate loans                
Schedule of Investments [Line Items]                
Nonaccrual loans, no allowance 279   279     30    
Allowance for credit losses 341 271 341 271 $ 315 277 $ 243 $ 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 141   141          
Allowance for credit losses 96   96          
Middle market loans                
Schedule of Investments [Line Items]                
Nonaccrual loans, no allowance 17   17     36    
Allowance for credit losses $ 258 $ 139 $ 258 $ 139 $ 209 $ 138 $ 127 $ 140
Geographic Concentration Risk | California | Mortgages                
Schedule of Investments [Line Items]                
Concentration risk, percentage     19.00%          
Geographic Concentration Risk | Texas | Mortgages                
Schedule of Investments [Line Items]                
Concentration risk, percentage     14.00%          
Geographic Concentration Risk | MASSACHUSETTS | Mortgages                
Schedule of Investments [Line Items]                
Concentration risk, percentage     8.00%          
[1] Net of allowance for credit losses