Financing Minimum Principle Payments (Details) - USD ($)		Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Principle due prior to 2019		$ 0
Principle due in 2019		800,000,000
Principle due in 2020		0
Principle due in 2021		750,000,000
Principle due thereafter		1,572,400,000
Long-term debt	[1]	3,122,400,000
Debt discounts, premiums and issuance costs		18,200,000	$ 20,100,000
Long-term Debt		4,056,200,000	3,358,000,000
Commercial Paper [Member]
Debt Instrument [Line Items]
Long-term Debt		948,600,000
Term Loan [Member]
Debt Instrument [Line Items]
Principle due in 2019		500,000,000
Principle due in 2020		0
Principle due in 2021		0
Principle due thereafter		122,400,000
Long-term debt	[1]	622,400,000
Senior Notes [Member]
Debt Instrument [Line Items]
Principle due in 2019		300,000,000
Principle due in 2020		0
Principle due in 2021		750,000,000
Principle due thereafter		1,450,000,000
Long-term debt	[1]	2,500,000,000
Other Debt [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 3,400,000	$ 3,300,000

[1] Not included in the table above are net discounts, premiums and issuance costs associated with the Registered Notes, which totaled $18.2 million as of December 31, 2017, and have been recorded as an offset to the carrying amount of the related debt in the accompanying Consolidated Balance Sheet as of December 31, 2017. In addition, the table above does not include principal balances of $948.6 million under the Commercial Paper Programs and other financing balances of $3.4 million.