Commitments and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Operating lease obligations:
Lease and rental expense included in costs and expenses	$ 25.8	$ 25.9	$ 51.4	$ 52.1
New Purchase Obligations [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Unrecorded purchase obligation, next five years	1,200.0		1,200.0
Unrecorded purchase obligation, in total	1,700.0		1,700.0
Litigation matters [Member]
Loss Contingencies [Line Items]
Litigation accruals on an undiscounted basis	$ 4.5		4.5		$ 4.5
Litigation matters [Member] | ETP Lawsuit [Member]
Loss Contingencies [Line Items]
Loss contingency, damages awarded			319.4
Loss contingency, total damages sought			535.8
Loss contingency, disgorgement damages sought			150.0
Prejudgment interest			$ 66.4
Post-judgment interest rate			5.00%
Positive Outcome of Litigation [Member]
Gain Contingencies [Line Items]
Counterclaim settlement awarded			$ 0.8