Equity and Partners' Capital - Partnership Interests Table (Details) - Western Gas Partners, LP [Member]	9 Months Ended
	Sep. 30, 2018 shares
Change In Units [Roll Forward]
Balance	168,429,056
Units issued	801,546
Long-Term Incentive Plan award vestings	7,180
Balance	169,237,782
Common Units [Member]
Change In Units [Roll Forward]
Balance	152,602,105
Long-Term Incentive Plan award vestings	7,180
Balance	152,609,285
Class C Units [Member]
Change In Units [Roll Forward]
Balance	13,243,883
Units issued	801,546
Balance	14,045,429
General Partner [Member]
Change In Units [Roll Forward]
Balance	2,583,068
Balance	2,583,068