Equity Investments - Equity Investments Table (details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2015		Mar. 31, 2014	[5]
Schedule of Equity Method Investments [Line Items]
Balance	[1]	$ 634,492
Investment earnings (loss), net of amortization	[2],[3],[4]	18,220		$ 9,251
Contributions		4,878		28,462
Distributions	[3]	(18,706)		(10,269)
Distributions in excess of cumulative earnings	[3]	(2,964)	[6]	$ (2,044)
Balance		635,920
Western Gas Partners [Member] | Fort Union [Member]
Schedule of Equity Method Investments [Line Items]
Balance		25,933
Investment earnings (loss), net of amortization		1,555
Contributions		0
Distributions		(948)
Distributions in excess of cumulative earnings	[6]	0
Balance		26,540
Western Gas Partners [Member] | White Cliffs [Member]
Schedule of Equity Method Investments [Line Items]
Balance		44,315
Investment earnings (loss), net of amortization		3,980
Contributions		2,917
Distributions		(3,834)
Distributions in excess of cumulative earnings	[6]	(902)
Balance		46,476
Western Gas Partners [Member] | Rendezvous [Member]
Schedule of Equity Method Investments [Line Items]
Balance		56,336
Investment earnings (loss), net of amortization		377
Contributions		0
Distributions		(862)
Distributions in excess of cumulative earnings	[6]	(736)
Balance		55,115
Western Gas Partners [Member] | Mont Belvieu Joint Venture [Member]
Schedule of Equity Method Investments [Line Items]
Balance		121,337
Investment earnings (loss), net of amortization		5,791
Contributions		(432)
Distributions		(6,291)
Distributions in excess of cumulative earnings	[6]	0
Balance		120,405
Western Gas Partners [Member] | Texas Express Gathering Limited Liability Company [Member]
Schedule of Equity Method Investments [Line Items]
Balance		16,790
Investment earnings (loss), net of amortization		190
Contributions		0
Distributions		(337)
Distributions in excess of cumulative earnings	[6]	0
Balance		16,643
Western Gas Partners [Member] | Texas Express Pipeline Limited Liability Company [Member]
Schedule of Equity Method Investments [Line Items]
Balance		198,793
Investment earnings (loss), net of amortization		3,616
Contributions		1,180
Distributions		(3,679)
Distributions in excess of cumulative earnings	[6]	(581)
Balance		199,329
Western Gas Partners [Member] | Front Range Pipeline Limited Liability Company [Member]
Schedule of Equity Method Investments [Line Items]
Balance		170,988
Investment earnings (loss), net of amortization		2,711
Contributions		1,213
Distributions		(2,755)
Distributions in excess of cumulative earnings	[6]	(745)
Balance		$ 171,412

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

[4] 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.

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

[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.