Basis of Presentation Recent Accounting Pronouncements (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in operating income	$ 146,400,000	$ 136,000,000	$ 381,100,000	$ 370,000,000
Impact on Other expense, net	(1,100,000)	$ (300,000)	(5,500,000)	(5,600,000)
Accounting Standards Update 2017-07 | Pro Forma
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in operating income			15,000,000	12,000,000
Impact on Other expense, net			0	$ 0
Accounting Standards Update 2016-02 | Pro Forma
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease, right-of-use asset (less than)	$ 100,000,000		$ 100,000,000