Equity and Partners' Capital - Partnership Interests Table (Details) - Western Gas Partners, LP [Member]	3 Months Ended
	Mar. 31, 2018 shares
Change In Units [Roll Forward]
Balance	168,429,056
Units issued	261,394
Balance	168,690,450
Common Units [Member]
Change In Units [Roll Forward]
Balance	152,602,105
Balance	152,602,105
Class C Units [Member]
Change In Units [Roll Forward]
Balance	13,243,883
Units issued	261,394
Balance	13,505,277
General Partner [Member]
Change In Units [Roll Forward]
Balance	2,583,068
Balance	2,583,068