Debt and Interest Expense - Western Gas Partners, LP (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit, maximum capacity	$ 5,000,000,000
Line of credit, expiration date	Sep. 02, 2015
Revolving Credit Facility [Member] | Minimum [Member] | London Interbank Offered Rate [Member]
Line of Credit Facility [Line Items]
Margin added to LIBOR	1.25%
Revolving Credit Facility [Member] | Maximum [Member] | London Interbank Offered Rate [Member]
Line of Credit Facility [Line Items]
Margin added to LIBOR	2.50%
Western Gas Partners Limited Partnership [Member] | Minimum [Member] | London Interbank Offered Rate [Member]
Line of Credit Facility [Line Items]
Margin added to LIBOR	1.30%
Western Gas Partners Limited Partnership [Member] | Maximum [Member] | London Interbank Offered Rate [Member]
Line of Credit Facility [Line Items]
Margin added to LIBOR	1.90%
Western Gas Partners Limited Partnership [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit, maximum capacity	$ 800,000,000
Line of credit, expiration date	Mar. 24, 2016