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, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Gains (losses) on commodity price swap
Net gains (losses) on commodity price swap agreements	$ 10,562		$ 9,315		$ 31,143		$ 6,406
Sales [Member]
Gains (losses) on commodity price swap
Net gains (losses) on commodity price swap agreements	34,464	[1]	35,118	[1]	97,756	[1]	76,748	[1]
Cost of Sales [Member]
Gains (losses) on commodity price swap
Net gains (losses) on commodity price swap agreements	(23,902)	[2]	(25,803)	[2]	(66,613)	[2]	(70,342)	[2]
Natural Gas, Per Thousand Cubic Feet [Member] | Sales [Member]
Gains (losses) on commodity price swap
Net gains (losses) on commodity price swap agreements	6,923	[1]	9,132	[1]	14,707	[1]	30,728	[1]
Natural Gas Liquids [Member] | Sales [Member]
Gains (losses) on commodity price swap
Net gains (losses) on commodity price swap agreements	$ 27,541	[1]	$ 25,986	[1]	$ 83,049	[1]	$ 46,020	[1]

[1] Reported in affiliate natural gas, NGLs 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.