Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended					9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 New Lease Agreements [Member]	Sep. 30, 2014 Litigation matters [Member]	Dec. 31, 2013 Litigation matters [Member]	Sep. 30, 2014 Litigation matters [Member] ETP Lawsuit [Member]
Loss Contingencies [Line Items]
Litigation accruals on an undiscounted basis						$ 2.5	$ 3.7
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 (in hundredths)								5.00%
Operating lease obligations [Abstract]
Lease and rental expense included in costs and expenses	23.5	19.6	69.2	64.9
Contractual obligation [Line Items]
Total lease commitments over the next five years					39
Total lease commitments					$ 150