Recent Authoritative Accounting Guidance (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent	$ 3,447.0	$ 3,304.0	$ 3,227.5	$ 3,073.8
Off-Balance Sheet, Credit Loss, Liability	5.9	5.2	18.4
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent	$ 1,274.2	$ 1,166.4	$ 1,135.1	$ 1,072.7