v3.26.3
Separate Account Balances - Benefits and Protection (Details) - USD ($)
$ in Millions
9 Months Ended 12 Months Ended
Sep. 30, 2026
Dec. 31, 2025
Changes in separate account liabilities    
Balance at beginning of period $ 193,622.6  
Balance at end of period 194,816.2 $ 193,622.6
Benefits and Protection | Life Insurance | Universal life    
Changes in separate account liabilities    
Balance at beginning of period 7,807.9 6,806.7
Premiums and deposits 422.8 572.7
Policy charges (104.9) (135.4)
Surrenders, withdrawals and benefit payments (355.0) (374.4)
Investment performance 536.8 938.5
Net transfers (to) from general account 21.6 (0.2)
Balance at end of period 8,329.2 7,807.9
Cash surrender value $ 8,406.7 $ 7,873.6