Debt and Interest Expense - Debt Outstanding Table (details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Debt Instrument [Line Items]
Principal	$ 1,920,000		$ 1,420,000
Carrying value	1,912,839		1,418,169	[1]
Fair value	1,973,865	[2]	1,422,840	[2]
Senior Notes 5 Point 375 Percent Due 2021 [Member] | Western Gas Partners [Member]
Debt Instrument [Line Items]
Principal	500,000		500,000
Carrying value	495,305		495,173
Fair value	548,287	[2]	533,615	[2]
Senior Notes 4 Percent Due 2022 [Member] | Western Gas Partners [Member]
Debt Instrument [Line Items]
Principal	670,000		670,000
Carrying value	673,192		673,278
Fair value	666,755	[2]	641,237	[2]
Senior Notes 2 Point 6 Percent Due 2018 [Member] | Western Gas Partners [Member]
Debt Instrument [Line Items]
Principal	350,000		250,000
Carrying value	350,567		249,718
Fair value	352,159	[2]	247,988	[2]
Senior Notes 5 Point 45 Percent Due 2044 [Member] | Western Gas Partners [Member]
Debt Instrument [Line Items]
Principal	400,000		0
Carrying value	393,775		0
Fair value	$ 406,664	[2]	$ 0	[2]

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

[2] Fair value is measured using Level 2 inputs.