Basis of Presentation and Summary of Significant Accounting Policies Cash flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Capital Expenditures Incurred but Not yet Paid	$ 210.3	$ 177.4	$ 59.8
Cash paid for interest	350.3	162.5	98.9
Cash paid for taxes, net of refunds	$ (86.0)	$ 165.0	$ 134.1