Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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Debt and Interest Expense - Debt Activity Table (details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Beginning balance			$ 1,168,278
Ending balance	2,424,104	1,418,169	1,168,278
Western Gas Partners [Member]
Debt Instrument [Line Items]
Other	(5,215)	109
Western Gas Partners [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Borrowings	1,160,000	710,000
Repayments	(650,000)	(710,000)
Western Gas Partners [Member] \| Senior Notes 5 Point 45 Percent Due 2044 [Member]
Debt Instrument [Line Items]
Borrowings	400,000
Western Gas Partners [Member] \| Senior Notes 2 Point 6 Percent Due 2018 [Member]
Debt Instrument [Line Items]
Borrowings	100,000	250,000
Anadarko [Member] \| Working Capital Facility [Member]
Debt Instrument [Line Items]
WGP working capital facility borrowings	$ 1,150