v3.26.1
Debt (Tables)
6 Months Ended
Jun. 30, 2026
Debt Disclosure [Abstract]  
Schedule of Long-term Debt Instruments Total amortized cost of Long-term Debt, Non-Current outstanding at June 30, 2026 and December 31, 2025 was:
(Dollars in Millions)Jun 30,
2026
Dec 31,
2025
Non-Current:
    2.400% Senior Notes due September 30, 2030
$398.1 $397.9 
    3.800% Senior Notes due February 23, 2032
397.2 396.9 
5.875% Fixed-Rate Reset Junior Subordinated Debentures due 2062
149.2 148.7 
Total Long-term Debt Outstanding$944.5 $943.5