Description of Business and Basis of Presentation - Asset Table (details) (Western Gas Partners [Member])	Sep. 30, 2014 unit
Operated [Member] | Natural Gas Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	13
Operated [Member] | Natural Gas Treating Facilities [Member]
Assets [Line Items]
Assets, number of units	8
Operated [Member] | Natural Gas Processing Facilities [Member]
Assets [Line Items]
Assets, number of units	9
Operated [Member] | Natural Gas Liquids Pipelines [Member]
Assets [Line Items]
Assets, number of units	3
Operated [Member] | Natural Gas Pipelines [Member]
Assets [Line Items]
Assets, number of units	3
Operated Interests [Member] | Natural Gas Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	1
Operated Interests [Member] | Natural Gas Processing Facilities [Member]
Assets [Line Items]
Assets, number of units	3
Non-Operated Interests [Member] | Natural Gas Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	5
Equity Interests [Member] | Natural Gas Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	2
Equity Interests [Member] | Natural Gas Liquids Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	2
Equity Interests [Member] | Natural Gas Treating Facilities [Member]
Assets [Line Items]
Assets, number of units	1
Equity Interests [Member] | Natural Gas Processing Facilities [Member]
Assets [Line Items]
Assets, number of units	2
Equity Interests [Member] | Natural Gas Liquids Pipelines [Member]
Assets [Line Items]
Assets, number of units	2
Equity Interests [Member] | Oil Pipeline [Member]
Assets [Line Items]
Assets, number of units	1