Equity and Partners' Capital - Partnership Interests Table (Details) - Western Gas Partners, LP [Member] - shares			1 Months Ended	3 Months Ended		12 Months Ended
		Mar. 14, 2016	Apr. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Capital Unit [Line Items]
Balance					142,571,895	167,535,992	142,571,895
Units issued						885,760	946,261
Long-Term Incentive Plan award vestings						7,304	5,403
Conversion of Series A Preferred units						0
Balance						168,429,056	167,535,992
Common Units [Member]
Capital Unit [Line Items]
Balance					128,576,965	130,671,970	128,576,965
Long-Term Incentive Plan award vestings						7,304	5,403
Conversion of Series A Preferred units						21,922,831
Balance						152,602,105	130,671,970
Class C Units [Member]
Capital Unit [Line Items]
Balance					11,411,862	12,358,123	11,411,862
Units issued						885,760	946,261
Balance						13,243,883	12,358,123
Series A Preferred Units [Member]
Capital Unit [Line Items]
Balance					0	21,922,831	0
Conversion of Series A Preferred units						(21,922,831)
Balance						0	21,922,831
General Partner [Member]
Capital Unit [Line Items]
Balance					2,583,068	2,583,068	2,583,068
Balance						2,583,068	2,583,068
Private Investor [Member] | Series A Preferred Units [Member]
Capital Unit [Line Items]
Units issued		14,030,611			14,030,611
Private Investor [Member] | Over-Allotment Option [Member]
Capital Unit [Line Items]
Units issued							7,892,220
Private Investor [Member] | Over-Allotment Option [Member] | Series A Preferred Units [Member]
Capital Unit [Line Items]
Units issued			7,892,220	7,892,220			7,892,220
Springfield [Member]
Capital Unit [Line Items]
WES units issued, acquisition							16,120,213
Springfield [Member] | Common Units [Member]
Capital Unit [Line Items]
Units issued	[1]	2,089,602
WES units issued, acquisition							2,089,602
Springfield [Member] | Series A Preferred Units [Member]
Capital Unit [Line Items]
Units issued	[1]	14,030,611
WES units issued, acquisition							14,030,611

[1] WES acquired Springfield Pipeline LLC (“Springfield”) from Anadarko for $750.0 million, consisting of $712.5 million in cash and the issuance of 1,253,761 of WES common units. Springfield owns a 50.1% interest in an oil gathering system and a gas gathering system. The Springfield oil and gas gathering systems (collectively, the “Springfield system”) are located in Dimmit, La Salle, Maverick and Webb Counties in South Texas. WES financed the cash portion of the acquisition through: (i) borrowings of $247.5 million on the WES RCF, (ii) the issuance of 835,841 of WES common units to WGP and (iii) the issuance of WES Series A Preferred units to private investors. See Note 4 for further information regarding WES’s Series A Preferred units. WGP financed the purchase of the WES common units by borrowing $25.0 million under the WGP RCF. See Note 12.