Summary of Significant Accounting Policies (Schedule of Cash and Cash Equivalents) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 8.5	$ 187.4	$ 19.7	$ 25.7
Restricted cash and cash equivalents	382.7	330.3	328.8	303.6
Total cash, cash equivalents, restricted cash and restricted cash equivalents	$ 391.2	$ 517.7	$ 348.5	$ 329.3