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Supplemental cash flow information (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Condensed Cash Flow Statements, Captions [Line Items]
Interest	$ 54.0	$ 40.9
Income taxes, net	38.9	42.8
Financing Leases	44.4	19.4
Restricted cash	279.8		$ 322.0
Cash and cash equivalents	661.6		620.9
Cash, Cash Equivalents, and Restricted Cash	941.4	$ 702.8	942.9	$ 469.0
Cash Held From Customers
Condensed Cash Flow Statements, Captions [Line Items]
Restricted cash	133.6		199.5
Deposits liability
Condensed Cash Flow Statements, Captions [Line Items]
Restricted cash	136.0		113.7
Revolving Credit Facility
Condensed Cash Flow Statements, Captions [Line Items]
Restricted cash	$ 7.5		$ 5.0