Transactions With Affiliates - Additional Information (details) (USD $)				1 Months Ended	9 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended		9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012		May 31, 2008 Note Receivable From Anadarko [Member] Western Gas Partners [Member]	Sep. 30, 2013 Note Receivable From Anadarko [Member] Western Gas Partners [Member]	Dec. 31, 2012 Note Receivable From Anadarko [Member] Western Gas Partners [Member]	Sep. 30, 2013 Note Payable To Anadarko [Member] Western Gas Partners [Member]	Dec. 31, 2008 Note Payable To Anadarko [Member] Western Gas Partners [Member]	Jun. 30, 2012 Senior Notes 4 Percent Due 2022 [Member] Western Gas Partners [Member]	Sep. 30, 2013 Gathering Transportation And Treating [Member] Western Gas Partners [Member]	Sep. 30, 2012 Gathering Transportation And Treating [Member] Western Gas Partners [Member]	Sep. 30, 2013 Gathering Transportation And Treating [Member] Western Gas Partners [Member]	Sep. 30, 2012 Gathering Transportation And Treating [Member] Western Gas Partners [Member]	Sep. 30, 2013 Processing [Member] Western Gas Partners [Member]	Sep. 30, 2012 Processing [Member] Western Gas Partners [Member]	Sep. 30, 2013 Processing [Member] Western Gas Partners [Member]	Sep. 30, 2012 Processing [Member] Western Gas Partners [Member]	Sep. 30, 2013 Long Term Incentive Plan [Member]	Sep. 30, 2013 Long Term Incentive Plan [Member]	Sep. 30, 2013 Long Term Incentive Plan [Member] Western Gas Partners [Member]	Sep. 30, 2012 Long Term Incentive Plan [Member] Western Gas Partners [Member]	Sep. 30, 2013 Long Term Incentive Plan [Member] Western Gas Partners [Member]	Sep. 30, 2012 Long Term Incentive Plan [Member] Western Gas Partners [Member]	Sep. 30, 2013 Anadarko Incentive Plans [Member] Western Gas Partners [Member]	Sep. 30, 2012 Anadarko Incentive Plans [Member] Western Gas Partners [Member]	Sep. 30, 2013 Anadarko Incentive Plans [Member] Western Gas Partners [Member]	Sep. 30, 2012 Anadarko Incentive Plans [Member] Western Gas Partners [Member]	Sep. 30, 2012 Incentive Plan [Member] Western Gas Partners [Member]	Sep. 30, 2012 Incentive Plan [Member] Western Gas Partners [Member]	Sep. 30, 2012 Incentive Plan [Member] Unit Appreciation Right [Member] Western Gas Partners [Member]	Sep. 30, 2013 Independent Director [Member] Long Term Incentive Plan [Member]	Sep. 30, 2013 Independent Director [Member] Long Term Incentive Plan [Member] Western Gas Partners [Member]
Related Party Transaction [Line Items]
Note receivable, due date					May 14, 2038
Note receivable - Anadarko	$ 260,000,000	$ 260,000,000	[1]	$ 260,000,000
Debt instrument, maturity date							Aug. 02, 2013
Fixed annual rate for note receivable bearing interest				6.50%
The fair value of the note receivable					301,500,000	334,800,000
Principal	1,520,000,000	1,170,000,000						175,000,000
Fixed interest rate									4.00%
Affiliate throughput percent										56.00%	63.00%	58.00%	64.00%	58.00%	61.00%	56.00%	59.00%
Phantom units vesting term																						3 years									1 year	1 year
Equity based compensation expense																		$ 100,000	$ 200,000	$ 100,000	$ 100,000	$ 400,000	$ 300,000	$ 800,000	$ 800,000	$ 2,200,000	$ 2,400,000	$ 8,600,000	$ 13,900,000
UVR, UAR and DER Valuation																														$ 1,053

[1] Financial information has been recast to include the financial position and results attributable to the Non-Operated Marcellus Interest. See Note 2.