Debt and Interest Expense - Additional Information (details) (USD $)	12 Months Ended			1 Months Ended		0 Months Ended		1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Nov. 30, 2012	Feb. 28, 2014	Mar. 03, 2014		Mar. 31, 2014	Jun. 30, 2012	Mar. 31, 2011	Dec. 31, 2010	Dec. 31, 2008
Debt Instrument [Line Items]
Borrowings	$ 1,648,028,000	$ 957,503,000	$ 1,041,648,000
Working Capital Facility [Member] | Anadarko [Member]
Debt Instrument [Line Items]
Principal	1,150,000	0
Line of credit, expiration date	Nov. 01, 2017
Revolving credit facility, maximum borrowing capacity				30,000,000
Interest rate percent above LIBOR				1.50%
Revolving credit facility, interest rate at period end	1.67%	1.67%
Borrowings	1,200,000
Available borrowing capacity	28,900,000
Western Gas Partners [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Principal	510,000,000	0
Line of credit, expiration date	Feb. 26, 2019
Revolving credit facility, maximum borrowing capacity					1,200,000,000					800,000,000
Revolving credit facility, expandable maximum borrowing capacity					1,500,000,000
Revolving credit facility, interest rate at period end	1.47%	1.67%
Facility fee	0.20%	0.25%
Outstanding borrowings	510,000,000
Outstanding letters of credit	12,800,000
Available borrowing capacity	677,200,000
Western Gas Partners [Member] | Revolving Credit Facility [Member] | Alternate Base Rate [Member]
Debt Instrument [Line Items]
Interest rate percent above LIBOR					1.00%
Western Gas Partners [Member] | Minimum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Interest rate percent above LIBOR					0.975%
Facility fee					0.15%
Western Gas Partners [Member] | Minimum [Member] | Revolving Credit Facility [Member] | Alternate Base Rate [Member]
Debt Instrument [Line Items]
Interest rate percent above LIBOR					0.00%
Western Gas Partners [Member] | Maximum [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Interest rate percent above LIBOR					1.45%
Facility fee					0.30%
Western Gas Partners [Member] | Maximum [Member] | Revolving Credit Facility [Member] | Alternate Base Rate [Member]
Debt Instrument [Line Items]
Interest rate percent above LIBOR					0.45%
Western Gas Partners [Member] | Texas Express And Front Range [Member]
Debt Instrument [Line Items]
Borrowings						350,000,000	[1]
Western Gas Partners [Member] | Texas Express And Front Range [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Borrowings								350,000,000
Western Gas Partners [Member] | Senior Notes 5 Point 375 Percent Due 2021 [Member]
Debt Instrument [Line Items]
Fixed interest rate	5.375%
Principal	500,000,000	500,000,000
Debt instrument, maturity date	Jun. 01, 2021
Western Gas Partners [Member] | Senior Notes 4 Percent Due 2022 [Member]
Debt Instrument [Line Items]
Fixed interest rate	4.00%
Principal	670,000,000	670,000,000
Debt instrument, maturity date	Jul. 01, 2022
Western Gas Partners [Member] | Senior Notes 4 Percent Due 2022 [Member] | Interest Rate Swap [Member]
Debt Instrument [Line Items]
Accelerated amortization expense									1,700,000
Western Gas Partners [Member] | Senior Notes 2 Point 6 Percent Due 2018 [Member]
Debt Instrument [Line Items]
Fixed interest rate	2.60%
Offering percent								100.857%
Effective interest rate	2.743%
Underwriting discount								600,000
Principal	350,000,000	250,000,000
Debt instrument, maturity date	Aug. 15, 2018
Western Gas Partners [Member] | Senior Notes 5 Point 45 Percent Due 2044 [Member]
Debt Instrument [Line Items]
Fixed interest rate	5.45%
Offering percent								98.443%
Effective interest rate	5.633%
Underwriting discount								3,500,000
Principal	400,000,000	0
Debt instrument, maturity date	Apr. 01, 2044
Western Gas Partners [Member] | Note Payable To Anadarko [Member]
Debt Instrument [Line Items]
Fixed interest rate											2.82%
Principal												$ 175,000,000
Debt instrument, maturity date	Aug. 02, 2013
Western Gas Partners [Member] | Percentage Above Federal Funds Effective Rate [Member] | Revolving Credit Facility [Member] | Alternate Base Rate [Member]
Debt Instrument [Line Items]
Interest rate percent above LIBOR					0.50%

[1] WES acquired a 20% interest in each of TEG and TEP and a 33.33% interest in FRP from Anadarko. These assets gather and transport NGLs primarily from the Anadarko and Denver-Julesburg (“DJ”) Basins. The interests in these entities are accounted for under the equity method of accounting. In connection with the issuance of WES common units, WES GP purchased 6,296 general partner units in exchange for WES GP’s proportionate capital contribution of $0.4 million.