Consolidated Statements of Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Cost of product	$ 93,516	[1]	$ 89,107	[1],[2]	$ 270,059	[1]	$ 254,719	[1],[2]
Operation and maintenance	42,757	[1]	35,493	[1],[2]	121,165	[1]	103,304	[1],[2]
General and administrative	7,962	[1]	15,039	[1],[2]	25,100	[1]	35,623	[1],[2]
Interest expense	13,018	[3]	10,977	[2],[3]	37,483	[3]	30,118	[2],[3]
Affiliated Entity [Member]
Cost of product	33,753	[4]	42,839	[4]	97,801	[4]	115,603	[4]
Operation and maintenance	13,469	[5]	12,638	[5]	41,021	[5]	38,040	[5]
General and administrative	6,090	[6]	14,227	[6]	17,981	[6]	30,811	[6]
Interest expense	$ 0	[7]	$ 81	[7]	$ 0	[7]	$ 2,684	[7]

[1] Cost of product includes product purchases from Anadarko (as defined in Note 1) of $33.8 million and $97.8 million for the three and nine months ended September 30, 2013, respectively, and $42.8 million and $115.6 million for the three and nine months ended September 30, 2012, respectively. Operation and maintenance includes charges from Anadarko of $13.5 million and $41.0 million for the three and nine months ended September 30, 2013, respectively, and $12.6 million and $38.0 million for the three and nine months ended September 30, 2012, respectively. General and administrative includes charges from Anadarko of $6.1 million and $18.0 million for the three and nine months ended September 30, 2013, respectively, and $14.2 million and $30.8 million for the three and nine months ended September 30, 2012, respectively. See Note 5.

[2] Financial information has been recast to include the financial position and results attributable to the Non-Operated Marcellus Interest. See Note 2.

[3] Includes affiliate (as defined in Note 1) interest expense of zero for the three and nine months ended September 30, 2013, and $0.1 million and $2.7 million for the three and nine months ended September 30, 2012, respectively. See Note 8.

[4] Represents amounts recognized under gathering, treating or processing agreements, and purchase and sale agreements.

[5] 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.

[6] Represents general and administrative expense incurred on and subsequent to the date of WES’s acquisition of WES assets, as well as a management services fee for reimbursement of 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 by Anadarko (see Equity incentive plan and Anadarko incentive plans within this Note 5) and amounts charged by Anadarko under the WGP omnibus agreement.

[7] For the three and nine months ended September 30, 2012, includes interest expense recognized on the WES note payable to Anadarko (see Note 8) and interest imputed on the reimbursement payable to Anadarko for certain expenditures Anadarko incurred in 2011 related to the construction of the Brasada and Lancaster plants. WES repaid the WES note payable to Anadarko in June 2012, and repaid the reimbursement payable to Anadarko related to the construction of the Brasada and Lancaster plants in the fourth quarter of 2012. See Note receivable from and amounts payable to Anadarko within this Note 5.