Property, Plant and Equipment - Historical Cost Table (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 8,912,755	$ 7,864,535
Less accumulated depreciation	2,494,121	2,133,644
Net property, plant and equipment	6,418,634	5,730,891
Western Gas Partners, LP [Member] \| Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	4,653	4,450
Western Gas Partners, LP [Member] \| Gathering Systems and Processing Complexes [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 7,883,265	7,113,114
Western Gas Partners, LP [Member] \| Gathering Systems and Processing Complexes [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Western Gas Partners, LP [Member] \| Gathering Systems and Processing Complexes [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	47 years
Western Gas Partners, LP [Member] \| Pipelines and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 137,769	137,644
Western Gas Partners, LP [Member] \| Pipelines and Equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Western Gas Partners, LP [Member] \| Pipelines and Equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	45 years
Western Gas Partners, LP [Member] \| Assets Under Construction [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 856,092	579,501
Western Gas Partners, LP [Member] \| Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 30,976	$ 29,826
Western Gas Partners, LP [Member] \| Other [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Western Gas Partners, LP [Member] \| Other [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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