Equity Investments - Equity Investments Table (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	[4]	Jun. 30, 2015		Jun. 30, 2014	[4]
Schedule of Equity Method Investments [Line Items]
Balance	[1]				$ 634,492
Investment earnings (loss), net of amortization	[2],[3]	$ 18,941	$ 13,008		37,161	[5]	$ 22,259	[5]
Contributions					6,770		60,102
Distributions	[5]				(39,034)		(26,793)
Distributions in excess of cumulative earnings	[5]				(8,538)	[6]	$ (9,848)
Balance		630,851			630,851
Western Gas Partners, LP [Member] | Fort Union [Member]
Schedule of Equity Method Investments [Line Items]
Balance					25,933
Investment earnings (loss), net of amortization					3,191
Contributions					0
Distributions					(3,656)
Distributions in excess of cumulative earnings	[6]				0
Balance		25,468			25,468
Western Gas Partners, LP [Member] | White Cliffs [Member]
Schedule of Equity Method Investments [Line Items]
Balance					44,315
Investment earnings (loss), net of amortization					7,214
Contributions					4,370
Distributions					(6,923)
Distributions in excess of cumulative earnings	[6]				(2,026)
Balance		46,950			46,950
Western Gas Partners, LP [Member] | Rendezvous [Member]
Schedule of Equity Method Investments [Line Items]
Balance					56,336
Investment earnings (loss), net of amortization					1,001
Contributions					0
Distributions					(1,972)
Distributions in excess of cumulative earnings	[6]				(1,863)
Balance		53,502			53,502
Western Gas Partners, LP [Member] | Mont Belvieu JV [Member]
Schedule of Equity Method Investments [Line Items]
Balance					121,337
Investment earnings (loss), net of amortization					11,377
Contributions					(433)
Distributions					(12,035)
Distributions in excess of cumulative earnings	[6]				(1,025)
Balance		119,221			119,221
Western Gas Partners, LP [Member] | Texas Express Gathering LLC [Member]
Schedule of Equity Method Investments [Line Items]
Balance					16,790
Investment earnings (loss), net of amortization					231
Contributions					0
Distributions					(436)
Distributions in excess of cumulative earnings	[6]				(80)
Balance		16,505			16,505
Western Gas Partners, LP [Member] | Texas Express Pipeline LLC [Member]
Schedule of Equity Method Investments [Line Items]
Balance					198,793
Investment earnings (loss), net of amortization					6,818
Contributions					1,430
Distributions					(6,944)
Distributions in excess of cumulative earnings	[6]				(2,798)
Balance		197,299			197,299
Western Gas Partners, LP [Member] | Front Range Pipeline LLC [Member]
Schedule of Equity Method Investments [Line Items]
Balance					170,988
Investment earnings (loss), net of amortization					7,329
Contributions					1,403
Distributions					(7,068)
Distributions in excess of cumulative earnings	[6]				(746)
Balance		$ 171,906			$ 171,906

[1] Financial information has been recast to include the financial position and results attributable to the DBJV system. See Note 1 and Note 2.

[2] Income earned from equity investments is classified as affiliate. See Note 1.

[3] Represents amounts earned or incurred on and subsequent to the date of acquisition of WES assets, as well as amounts earned or incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES, recognized under gathering, treating or processing agreements, and purchase and sale agreements. See Adjustments to Previously Issued Financial Statements in Note 1.

[4] Financial information has been recast to include the financial position and results attributable to the DBJV system. See Note 1 and Note 2.

[5] Income earned on, distributions from and contributions to equity investments are classified as affiliate. See Note 1.

[6] Distributions in excess of cumulative earnings, classified as investing cash flows in the consolidated statements of cash flows, is calculated on an individual investment basis.