Leases - Lease Assets and Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Lease Assets and Liabilities [Line Items]
Operating Lease, Right-of-Use Asset	$ 900.7	$ 853.9
Operating Lease, Liability, Current	154.2
Operating Lease, Liability, Noncurrent	747.0
Operating Lease, Liability	901.2	689.2
Third Party Lease [Member]
Lease Assets and Liabilities [Line Items]
Operating Lease, Right-of-Use Asset	245.1		$ 0.0
Operating Lease, Liability, Current	80.9		0.0
Operating Lease, Liability, Noncurrent	164.7		0.0
Lease with Affiliate [Member]
Lease Assets and Liabilities [Line Items]
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
Operating Lease, Liability		$ 604.4