Leases Lease Additional Information (Narrative) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating Lease, Liability	[1]	$ 1,128.0
Operating Lease, Right-of-Use Asset		1,016.7	$ 892.6
Other current liabilities (Note 10)		1,368.6	1,494.5
Accumulated deficit		(4,915.2)	(1,563.1)
Operating Lease, Liability, Current		247.0	$ 275.1
sale lease back initial payment [Line Items]
Gain (Loss) on Termination of Lease		3.1
Lease Initial Direct Cost Expense Commencement [Line Items]		1.8
Lease Initial Direct Cost Expense Commencement [Line Items]		$ 1.8

[1] Includes the current portion of $247.0 million for operating leases.