Leases Lease Additional Information (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019		Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2016
Lessee, Lease, Description [Line Items]
Operating Lease, Liability	$ 956.8	[1]	$ 1,189.6
Operating Lease, Right-of-Use Asset	892.6		1,115.5	$ 0.0
Impact of Restatement on Opening Retained Earnings, Net of Tax					$ 42.0
Other current liabilities (Note 10)	1,494.5			1,771.6
(Accumulated deficit) retained earnings	$ (1,563.1)			1,072.2
Short-term lease, lease term	12 months
Operating Lease, Liability, Current	$ 275.1			$ 0.0
Other Current Liabilities
Lessee, Lease, Description [Line Items]
Impact of Restatement on Opening Retained Earnings, Net of Tax					5.0
Other Liabilities
Lessee, Lease, Description [Line Items]
Impact of Restatement on Opening Retained Earnings, Net of Tax					37.0
Retained Earnings
Lessee, Lease, Description [Line Items]
(Accumulated deficit) retained earnings					3,231.4
Other Liabilities
Lessee, Lease, Description [Line Items]
Other Liabilities					131.3
Other Current Liabilities
Lessee, Lease, Description [Line Items]
Other current liabilities (Note 10)					$ 1,044.4
Minimum | Other Assets
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	60 days
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract	10 years
Maximum | Other Assets
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	5 years
Maximum | Commercial Real Estate
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	15 years
Lease Agreements
Lessee, Lease, Description [Line Items]
Unrecorded Unconditional Purchase Obligation	$ 236.2
Accounting Standards Update 2016-02 | Retained Earnings
Lessee, Lease, Description [Line Items]
Adoption of accounting standard			$ 1.8

[1] (b) Includes the current portion of 275.1 million for operating leases.