Debt and Interest Expense - Debt Outstanding Table (details) - USD ($)		Mar. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Total long-term debt principal		$ 2,540,000,000	$ 2,430,000,000
Carrying value		2,532,995,000	2,422,954,000	[1]
Fair value	[2]	2,647,557,000	2,511,253,000
Anadarko [Member]
Debt Instrument [Line Items]
WGP working capital facility - Anadarko		0	1,150,000	[1]
Anadarko [Member] | Working Capital Facility [Member]
Debt Instrument [Line Items]
Principal		0	1,150,000
WGP working capital facility - Anadarko		0	1,150,000
Fair value	[2]	0	1,150,000
Western Gas Partners [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Principal		620,000,000	510,000,000
Carrying value		620,000,000	510,000,000
Fair value	[2]	620,000,000	510,000,000
Western Gas Partners [Member] | Senior Notes [Member] | 5.375% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Principal		500,000,000	500,000,000
Carrying value		495,854,000	495,714,000
Fair value	[2]	555,175,000	549,530,000
Western Gas Partners [Member] | Senior Notes [Member] | 4.000% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Principal		670,000,000	670,000,000
Carrying value		672,841,000	672,930,000
Fair value	[2]	683,554,000	681,942,000
Western Gas Partners [Member] | Senior Notes [Member] | 2.600% Senior Notes due 2018 [Member]
Debt Instrument [Line Items]
Principal		350,000,000	350,000,000
Carrying value		350,443,000	350,474,000
Fair value	[2]	355,372,000	352,162,000
Western Gas Partners [Member] | Senior Notes [Member] | 5.450% Senior Notes due 2044 [Member]
Debt Instrument [Line Items]
Principal		400,000,000	400,000,000
Carrying value		393,857,000	393,836,000
Fair value	[2]	$ 433,456,000	$ 417,619,000

[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] Fair value is measured using Level 2 inputs.