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.

[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.