Description of the Business and Significant Accounting Policies (Cash and Equivalents, and Restricted Cash and Equivalents) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Description of the Business and Significant Accounting Policies
Restricted Cash and Cash Equivalents	$ 5.5	$ 5.6	$ 5.5	$ 5.5
Restricted Cash and Cash Equivalents, Asset, Statement of Financial Position [Extensible List]	Other assets	Other assets	Other assets	Other assets