Acquisitions - Impact to Historical Consolidated Statement of Income Table (details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Revenues	$ 375,094		$ 293,717	[1]
Equity income, net	18,220	[2],[3],[4]	9,251	[1],[2],[3],[4]
Net income	85,966		93,796	[1]
Delaware Basin JV Gathering LLC [Member]
Revenues			14,260
Equity income, net			0
Net income			3,621
WGP Historical [Member]
Revenues			279,457
Equity income, net			9,251
Net income			$ 90,175

[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] 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.

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

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