Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cost of product	[1]	$ 431,921	$ 908,693	$ 494,194
Operation and maintenance	[1]	414,784	315,994	308,010
General and administrative	[1]	63,735	50,668	49,248
Interest expense	[2]	(186,043)	(144,615)	(116,628)
Affiliates [Member]
Cost of product	[3]	193,663	86,010	80,455
Operation and maintenance	[4]	98,769	72,489	72,330
General and administrative	[5]	46,212	39,940	38,873
Interest expense	[6]	$ 0	$ (71)	$ 7,747

[1] Cost of product includes product purchases from affiliates (as defined in Note 1) of $193.7 million, $86.0 million and $80.5 million for the years ended December 31, 2018, 2017 and 2016, respectively. Operation and maintenance includes charges from affiliates of $98.8 million, $72.5 million and $72.3 million for the years ended December 31, 2018, 2017 and 2016, respectively. General and administrative includes charges from affiliates of $46.2 million, $39.9 million and $38.9 million for the years ended December 31, 2018, 2017 and 2016, respectively. See Note 6.

[2] Includes affiliate (as defined in Note 1) amounts of zero, $(0.1) million and $7.7 million for the years ended December 31, 2018, 2017 and 2016, respectively. See Note 3 and Note 13.

[3] Represents amounts earned or incurred on and subsequent to the date of the 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.

[4] Represents expenses incurred on and subsequent to the date of the acquisition of WES assets, as well as expenses incurred by Anadarko on a historical basis related to WES assets prior to the acquisition of such assets by WES.

[5] Represents general and administrative expense incurred on and subsequent to the date of the acquisition of WES assets, as well as a management services fee for expenses incurred by Anadarko for periods prior to the acquisition of WES assets by WES. These amounts include equity-based compensation expense allocated to WES and WGP by Anadarko (see WES LTIP and WGP LTIP and Anadarko Incentive Plan within this Note 6) and amounts charged by Anadarko under the WGP and WES omnibus agreements.

[6] Includes amounts related to the Deferred purchase price obligation - Anadarko (see Note 3 and Note 13).