Equity Investments - Equity Investments Table (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	[4]	Sep. 30, 2015		Sep. 30, 2014	[4]
Schedule of Equity Method Investments [Line Items]
Balance	[1]				$ 634,492
Investment earnings (loss), net of amortization	[2],[3]	$ 21,976	$ 19,063		59,137	[5]	$ 41,322	[5]
Contributions					9,052		63,267
Distributions	[5]				(60,645)		(43,061)
Distributions in excess of cumulative earnings	[5]				(12,409)	[6]	$ (14,387)
Balance		629,627			629,627
Western Gas Partners, LP [Member] | Fort Union [Member]
Schedule of Equity Method Investments [Line Items]
Balance					25,933
Investment earnings (loss), net of amortization					4,831
Contributions					0
Distributions					(4,606)
Distributions in excess of cumulative earnings	[6]				0
Balance		26,158			26,158
Western Gas Partners, LP [Member] | White Cliffs [Member]
Schedule of Equity Method Investments [Line Items]
Balance					44,315
Investment earnings (loss), net of amortization					10,663
Contributions					6,081
Distributions					(10,227)
Distributions in excess of cumulative earnings	[6]				(2,584)
Balance		48,248			48,248
Western Gas Partners, LP [Member] | Rendezvous [Member]
Schedule of Equity Method Investments [Line Items]
Balance					56,336
Investment earnings (loss), net of amortization					1,591
Contributions					0
Distributions					(3,047)
Distributions in excess of cumulative earnings	[6]				(2,708)
Balance		52,172			52,172
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					17,256
Contributions					(432)
Distributions					(17,924)
Distributions in excess of cumulative earnings	[6]				(1,987)
Balance		118,250			118,250
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					475
Contributions					0
Distributions					(685)
Distributions in excess of cumulative earnings	[6]				(82)
Balance		16,498			16,498
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					11,691
Contributions					1,520
Distributions					(11,880)
Distributions in excess of cumulative earnings	[6]				(4,302)
Balance		195,822			195,822
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					12,630
Contributions					1,883
Distributions					(12,276)
Distributions in excess of cumulative earnings	[6]				(746)
Balance		$ 172,479			$ 172,479

[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.