Summary Of Significant Accounting Policies Summary of Significant Accounting Policies (Schedule of Cash and Cash Equivalents) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Cash and cash equivalents	$ 25.7	$ 8.2	$ 14.6
Restricted cash and cash equivalents	303.6	255.6	224.7
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 329.3	$ 263.8	$ 239.3	$ 173.7