Supplemental Cash Flow Information - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 916.8	$ 813.2	$ 400.1	$ 895.3
Total cash, cash equivalents and restricted cash shown in the statements of cash flows	995.1	872.3	469.5	965.4
Prepaid expenses and other current assets
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash recorded in other current assets	$ 78.3	$ 59.1	$ 69.4	$ 70.1