Partnership Distributions - Additional Information (details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended				0 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014	Nov. 25, 2014
Distribution Made to Limited Partner [Line Items]
Partnership agreement day requirement of distribution of available cash	55 days
Total quarterly distribution per unit	$ 0.34250	[1]	$ 0.25000
Western Gas Partners [Member]
Distribution Made to Limited Partner [Line Items]
Partnership agreement day requirement of distribution of available cash	45 days
Total quarterly distribution per unit	$ 0.725	[2]	$ 0.625	$ 0.700
Western Gas Partners [Member] | Class C Units [Member]
Distribution Made to Limited Partner [Line Items]
Discount rate percentage					6.00%
PIK Class C unit distributions				45,711
Fair value of PIK Class C unit distributions				$ 3.1
Prorated period				37 days

[1] On April 20, 2015, the Board of Directors of WGP GP declared a cash distribution to WGP unitholders of $0.34250 per unit, or $75.0 million in aggregate. The cash distribution is payable on May 22, 2015, to WGP unitholders of record at the close of business on April 30, 2015.

[2] On April 20, 2015, the Board of Directors of WES GP declared a cash distribution to WES unitholders of $0.725 per unit, or $133.2 million in aggregate, including incentive distributions, but excluding distributions on WES Class C units (see WES Class C unit distributions below). The cash distribution is payable on May 13, 2015, to WES unitholders of record at the close of business on April 30, 2015.