v3.26.1
Fair Values of Financial Instruments Private Equity Partnerships (Details) - Private Equity Partnerships - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share    
Alternative Investments $ 1,425.1 $ 1,456.3
Alternative Investments, Unfunded Commitments 762.8 756.7
Private Credit    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share    
Alternative Investments 226.6 255.8
Alternative Investments, Unfunded Commitments 124.1 121.0
Private Credit | Not Redeemable    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share    
Alternative Investments [1] 181.5 205.9
Alternative Investments, Unfunded Commitments 111.4 108.3
Private Credit | Quarterly/ 90 days notice [Member]    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share    
Alternative Investments 45.1 49.9
Alternative Investments, Unfunded Commitments 12.7 12.7
Private Equity Limited Partnership    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share    
Alternative Investments 657.7 651.4
Alternative Investments, Unfunded Commitments 444.9 422.3
Private Equity Limited Partnership | Not Redeemable    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share    
Alternative Investments [2] 621.5 618.9
Alternative Investments, Unfunded Commitments 429.0 406.8
Private Equity Limited Partnership | Initial 5.5 year lock on each new investment / Quarterly after 5.5 year lock with 90 days notice    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share    
Alternative Investments 36.2 32.5
Alternative Investments, Unfunded Commitments 15.9 15.5
Real Assets    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share    
Alternative Investments 540.8 549.1
Alternative Investments, Unfunded Commitments 193.8 213.4
Real Assets | Not Redeemable    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share    
Alternative Investments [3] 501.6 511.4
Alternative Investments, Unfunded Commitments 193.8 213.4
Real Assets | Quarterly/ 90 days notice [Member]    
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share    
Alternative Investments 39.2 37.7
Alternative Investments, Unfunded Commitments $ 0.0 $ 0.0
[1] Private Credit - The limited partnerships described in this category employ various investment strategies, generally providing direct lending or other forms of debt financing including first-lien, second-lien, mezzanine, and subordinated loans. The limited partnerships have credit exposure to corporates, physical assets, and/or financial assets within a variety of industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail) in North
America and, to a lesser extent, outside of North America.  As of June 30, 2026, the estimated remaining life of the investments that do not allow for redemptions is approximately 57 percent in the next 3 years, 20 percent during the period from 3 to 5 years, and 23 percent during the period from 5 to 10 years.
[2] Private Equity - The limited partnerships described in this category employ various strategies generally investing in controlling or minority control equity positions directly in companies and/or assets across various industries (including manufacturing, healthcare, energy, business services, technology, materials, and retail), primarily in private markets within North America and, to a lesser extent, outside of North America.  As of June 30, 2026, the estimated remaining life of the investments that do not allow for redemptions is approximately 39 percent in the next 3 years, 8 percent during the period from 3 to 5 years, 52 percent during the period from 5 to 10 years, and 1 percent during the period from 10 to 15 years.
[3] Real Assets - The limited partnerships described in this category employ various strategies, which include investing in the equity and/or debt financing of physical assets, including infrastructure (energy, power, water/wastewater, communications), transportation (including airports, ports, toll roads, aircraft, railcars) and real estate in North America, Europe, South America, and Asia.  As of June 30, 2026, the estimated remaining life of the investments that do not allow for redemptions is approximately 38 percent in the next 3 years, 23 percent during the period from 3 to 5 years, and 39 percent during the period from 5 to 10 years.