Commitments and Contingencies (Narratives) (Details) MMBTU in Thousands, $ in Millions	9 Months Ended
	Sep. 30, 2016 USD ($) MMBTU
Commitments And Contingencies [Abstract]
Sempra capacity | MMBTU	50
Demand For Payment Sempra	$ 63.8
Contingency Lower Range Sempra	4.2
Contingency Upper Range Sempra	63.8
Demand for payment Rockies Express	303.2
Contingency Lower Range REX	19.0
Contingency Upper Range REX	303.3
Demand For Payment Sunoco	38.6
Sunoco Proof Of Claim	16.9
Big West Proof Of Claim	$ 32.6