Summary of Significant Accounting Policies - Assets and Investments Table (Details) - Western Gas Partners, LP [Member]	Dec. 31, 2016 unit
Operated [Member] | Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	11
Operated [Member] | Treating Facilities [Member]
Assets [Line Items]
Assets, number of units	12
Operated [Member] | Natural Gas Processing Plants/Trains [Member]
Assets [Line Items]
Assets, number of units	20
Operated [Member] | Natural Gas Liquids Pipelines [Member]
Assets [Line Items]
Assets, number of units	2
Operated [Member] | Natural Gas Pipelines [Member]
Assets [Line Items]
Assets, number of units	5
Operated Interests [Member] | Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	4
Operated Interests [Member] | Treating Facilities [Member]
Assets [Line Items]
Assets, number of units	12
Operated Interests [Member] | Natural Gas Processing Plants/Trains [Member]
Assets [Line Items]
Assets, number of units	5
Operated Interests [Member] | Oil Pipelines [Member]
Assets [Line Items]
Assets, number of units	1
Non-Operated Interests [Member] | Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	5
Equity Interests [Member] | Gathering Systems [Member]
Assets [Line Items]
Assets, number of units	2
Equity Interests [Member] | Treating Facilities [Member]
Assets [Line Items]
Assets, number of units	3
Equity Interests [Member] | Natural Gas Processing Plants/Trains [Member]
Assets [Line Items]
Assets, number of units	2
Equity Interests [Member] | Natural Gas Liquids Pipelines [Member]
Assets [Line Items]
Assets, number of units	3
Equity Interests [Member] | Oil Pipelines [Member]
Assets [Line Items]
Assets, number of units	1