Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 53.3
Operating Lease, Right-of-Use Asset	900.7	$ 853.9
Operating Lease, Liability, Current	154.2
Operating Lease, Liability, Noncurrent	$ 747.0
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	20 years
Hydrogen Supply [Member]
Lessee, Lease, Description [Line Items]
Lessee, Leases Not Yet Commenced, Liability	$ 212.6
Lease with Affiliate [Member]
Lessee, Lease, Description [Line Items]
Operating lease cost	27.1
Operating Lease, Right-of-Use Asset	655.6	$ 604.4	$ 0.0
Operating Lease, Liability, Current	73.3		0.0
Operating Lease, Liability, Noncurrent	$ 582.3		$ 0.0
Lease with Affiliate [Member] | Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	7 years
Lease with Affiliate [Member] | Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	15 years
Hydrogen Supply - Second Quarter 2020 [Member]
Lessee, Lease, Description [Line Items]
Lessee, Lease Not Yet Commenced, Term Of Contract	15 years