Debt and Interest Expense - Debt Activity Table (details) (USD $) In Thousands, unless otherwise specified				9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012		Sep. 30, 2013 Western Gas Partners [Member]	Sep. 30, 2013 Revolving Credit Facility [Member] Western Gas Partners [Member]	Sep. 30, 2013 Senior Notes 2 Point 6 Percent Due 2018 [Member] Western Gas Partners [Member]
Debt Instrument [Line Items]
Balance	$ 1,518,110	$ 1,168,278	[1]		$ 0	$ 0
Borrowings					595,000	250,000
Repayments					(495,000)
Other				(168)
Balance	$ 1,518,110	$ 1,168,278	[1]		$ 100,000	$ 249,705

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