Equity-Based Compensation - Award Activity Tables (Details) - $ / shares	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Western Gas Partners 2017 Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value per unit of non-vested phantom units at beginning of year	$ 0	$ 49.88	$ 55.73
Value per unit of phantom units granted during the period		0	49.88
Value per unit of phantom units vested during the period		$ 0	$ 55.73
Value per unit of phantom units converted during the period		49.88	0
Value per unit of non-vested phantom units at end of year		$ 0	$ 49.88
Non-vested units at beginning of year	0	8,020	7,180
Phantom units granted		0	8,020
Phantom units vested		0	(7,180)
Phantom units converted		(8,020)	0
Non-vested units at end of year		0	8,020
Time-vested [Member] \| Western Gas Equity Partners 2012 Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value per unit of non-vested phantom units at beginning of year	$ 0	$ 35.08	$ 43.39
Value per unit of phantom units granted during the period	15.49	29.75	35.08
Value per unit of phantom units vested during the period	9.54	31.62	43.39
Value per unit of phantom units forfeited during the period	$ 16.27	$ 0	$ 0
Value per unit of phantom units converted during the period	0	33.46	0
Value per unit of non-vested phantom units at end of year	$ 15.69	$ 0	$ 35.08
Non-vested units at beginning of year	0	7,128	5,763
Phantom units granted	1,442,821	25,212	7,128
Phantom units vested	(53,551)	(44,572)	(5,763)
Phantom units forfeited	(81,664)	0	0
Phantom units converted	0	12,232	0
Non-vested units at end of year	1,307,606	0	7,128
TUR award [Member] \| Western Gas Equity Partners 2012 Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value per unit of non-vested phantom units at beginning of year	$ 0
Value per unit of phantom units granted during the period	17.79
Value per unit of phantom units forfeited during the period	17.79
Value per unit of non-vested phantom units at end of year	$ 17.79	$ 0
Non-vested units at beginning of year	0
Phantom units granted	124,067
Phantom units forfeited	(15,586)
Non-vested units at end of year	108,481	0
ROA Awards [Member] \| Western Gas Equity Partners 2012 Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value per unit of non-vested phantom units at beginning of year	$ 0
Value per unit of phantom units granted during the period	16.27
Value per unit of phantom units forfeited during the period	16.27
Value per unit of non-vested phantom units at end of year	$ 17.97	$ 0
Non-vested units at beginning of year	0
Phantom units granted	124,067
Phantom units forfeited	(15,586)
Non-vested units at end of year	108,481	0

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

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-Publisher FASB
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-SubTopic 10
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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-Publisher FASB
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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Increase (decrease) due to equity-based payment instruments, excluding stock (or unit) options, that were converted during the reporting period (number of units).

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were converted during the period.

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