v3.26.1
Investments - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Schedule of Investments [Line Items]          
Allowance for credit losses $ 55   $ 55   $ 21
Other invested assets 11,130   11,130   10,839
Benefit expense 37,024 $ 36,706 72,639 $ 72,018  
Proceeds from sales, maturities, calls or redemptions of fixed maturity securities 2,854 2,682 5,796 6,021  
Accrued investment income receivable 322   322   295
Fair value of collateral received at time of securities lending transactions $ 2,833   $ 2,833   $ 2,691
Securities lending transactions ratio of fair value of collateral held to fair value of securities loaned 102.00%   102.00%   102.00%
United States Government securities          
Schedule of Investments [Line Items]          
Allowance for credit losses $ 0   $ 0   $ 0
Residential mortgage-backed securities          
Schedule of Investments [Line Items]          
Allowance for credit losses 2   2   3
Overnight and Continuous | Cash          
Schedule of Investments [Line Items]          
Collateral received for securities loaned, at carrying value 2,171   2,171   2,136
Overnight and Continuous | United States Government securities          
Schedule of Investments [Line Items]          
Collateral received for securities loaned, at carrying value 658   658   552
Overnight and Continuous | Residential mortgage-backed securities          
Schedule of Investments [Line Items]          
Collateral received for securities loaned, at carrying value 4   4   3
Mosaic Health          
Schedule of Investments [Line Items]          
Commitment to fund 70   70   70
Equity Method Investment, Additional Funding Commitment     34    
Mosaic Health | Equity Method Investee          
Schedule of Investments [Line Items]          
Benefit expense 193 171 386 346  
Line of Credit | Mosaic Health          
Schedule of Investments [Line Items]          
Line of credit facility, maximum borrowing capacity 200   200   200
Line of Credit | Mosaic Health | Equity Method Investee          
Schedule of Investments [Line Items]          
Other invested assets 282   282   282
Revolving Credit Facility | Mosaic Health          
Schedule of Investments [Line Items]          
Line of credit facility, maximum borrowing capacity 500   500   500
Line of Credit Facility, Fair Value of Amount Outstanding $ 100   $ 100   $ 100
Mosaic Health          
Schedule of Investments [Line Items]          
Ownership percentage 40.00%   40.00%   40.00%
Liberty Dental          
Schedule of Investments [Line Items]          
Ownership percentage 40.00%   40.00%   40.00%
Other invested assets $ 162   $ 162   $ 137
Benefit expense 123 $ 146 256 $ 292  
Redeemable preferred equity shares value $ 250   250   250
Redeemable preferred equity shares disbursed     $ 165   $ 165