Transactions With Affiliates - Commodity Price Swap Agreements Table (details) - Western Gas Partners [Member]	Mar. 31, 2015 $ / bbl $ / MMBTU
Ethane [Member] | Year 2015 [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	18.41
Ethane [Member] | Year 2015 [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	23.41
Ethane [Member] | Year 2016 [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	23.11
Propane [Member] | Year 2015 [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	47.08
Propane [Member] | Year 2015 [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	52.99
Propane [Member] | Year 2016 [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	52.90
Isobutane [Member] | Year 2015 [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	62.09
Isobutane [Member] | Year 2015 [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	74.02
Isobutane [Member] | Year 2016 [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	73.89
Normal Butane [Member] | Year 2015 [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	54.62
Normal Butane [Member] | Year 2015 [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	65.04
Normal Butane [Member] | Year 2016 [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	64.93
Natural Gasoline [Member] | Year 2015 [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	72.88
Natural Gasoline [Member] | Year 2015 [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	81.82
Natural Gasoline [Member] | Year 2016 [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	81.68
Condensate [Member] | Year 2015 [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	76.47
Condensate [Member] | Year 2015 [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	81.82
Condensate [Member] | Year 2016 [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price	81.68
Natural Gas (per MMbtu) [Member] | Year 2015 [Member] | Minimum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU	4.66
Natural Gas (per MMbtu) [Member] | Year 2015 [Member] | Maximum [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU	5.96
Natural Gas (per MMbtu) [Member] | Year 2016 [Member]
Commodity Price Risk Swap [Line Items]
Commodity swap fixed price | $ / MMBTU	4.87