INVESTMENTS - SUMMARY OF INVESTMENTS BY CONTRACTUAL MATURITY (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Amortized cost
Due in one year or less	$ 196.2
Due after one year through five years	2,296.8
Due after five years through ten years	3,325.0
Due after ten years	12,795.8
Subtotal	18,613.8
Structured securities	7,966.4
Amortized cost	26,580.2
Estimated fair value
Due in one year or less	196.2
Due after one year through five years	2,283.5
Due after five years through ten years	3,290.9
Due after ten years	10,954.5
Subtotal	16,725.1
Structured securities	7,770.6
Estimated fair value	$ 24,495.7	$ 23,886.8

Available For Sale Securities, Debt Maturities, Amortized Cost, Excluding Structured Securities

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