Supplemental Crude Oil, Natural Gas and NGLs Information - Unaudited Price Used to Estimate Reserves (Details) (USD $)
Dec. 31, 2013
Dec. 31, 2012
Oil (MBbl)
    
Reserve Quantities [Line Items]    
Price Used to Estimate Reserves $ 81.91 [1] $ 87.32 [1]
Natural Gas (MMcf)
    
Reserve Quantities [Line Items]    
Price Used to Estimate Reserves 2.96 [1] 2.18 [1]
Natural Gas Liquids (MBbl)
    
Reserve Quantities [Line Items]    
Price Used to Estimate Reserves $ 29.17 [1] $ 28.27 [1]
[1] The prices used to estimate reserves have been prepared in accordance with the SEC. Future estimated cash flows were based on a 12-month average price calculated as the unweighted arithmetic average of the prices on the first day of each month, January through December, applied to this Partnership's year-end estimated proved reserves. Prices for each of the two years were adjusted by field for Btu content, transportation and regional price differences; however, they were not adjusted to reflect the value of this Partnership's commodity derivatives.