Transactions With Affiliates - Gains Losses Commodity Price Swap Table (details) (Western Gas Partners [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Gains (losses) on commodity price swap
Net gains (losses) on commodity price swap agreements	$ 6,383		$ 10,562		$ 30,190		$ 31,143
Sales [Member]
Gains (losses) on commodity price swap
Net gains (losses) on commodity price swap agreements	25,916	[1]	34,464	[1]	68,271	[1]	97,756	[1]
Sales [Member] | Natural Gas [Member]
Gains (losses) on commodity price swap
Net gains (losses) on commodity price swap agreements	3,179	[1]	6,923	[1]	1,525	[1]	14,707	[1]
Sales [Member] | Natural Gas Liquids [Member]
Gains (losses) on commodity price swap
Net gains (losses) on commodity price swap agreements	22,737	[1]	27,541	[1]	66,746	[1]	83,049	[1]
Cost of Sales [Member]
Gains (losses) on commodity price swap
Net gains (losses) on commodity price swap agreements	$ (19,533)	[2]	$ (23,902)	[2]	$ (38,081)	[2]	$ (66,613)	[2]

[1] Reported in affiliate natural gas, natural gas liquids and condensate sales in the consolidated statements of income in the period in which the related sale is recorded.

[2] Reported in cost of product in the consolidated statements of income in the period in which the related purchase is recorded.