Price Risk Management Counterparties Representing 10% or More (Details)	Jun. 30, 2014	Dec. 31, 2013
Assets from price risk management activities:
Counterparty A	30.00%	53.00%
Counterparty B	19.00%	5.00%
Counterparty C	11.00%	6.00%
Concentration of Risk, Derivative Instruments, Assets	60.00%	64.00%
Liabilities from price risk management activities:
Counterparty D	50.00%	43.00%
Counterparty E	10.00%	11.00%
Concentration of Risk, Derivative Instruments, Liabilities	60.00%	54.00%