Summary Of Significant Accounting Policies Summary of Significant Accounting Policies (Schedule of Cash and Cash Equivalents) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 23.3	$ 16.0	$ 187.4
Restricted cash and cash equivalents	410.9	380.2	330.3
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 434.2	$ 396.2	$ 517.7	$ 329.3