Recent Authoritative Accounting Guidance (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent	$ 3,227.5	$ 3,073.8	$ 1,986.6	$ 1,959.8
Off-Balance Sheet, Credit Loss, Liability	18.4	16.2	3.8
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' Equity Attributable to Parent	$ 1,135.1	$ 1,072.7	$ 1,052.6	$ 962.1