Acquisitions and Divestitures	3 Months Ended
Mar. 31, 2013
Disclosure Text Block [Abstract]
Acquisitions and Divestitures	3. Acquisitions and Divestitures Acquisitions In March 2013, Western Gas Partners, LP (WES), a consolidated subsidiary of the Company, acquired a 33.75% interest in gas-gathering systems located in the Marcellus shale in north-central Pennsylvania from a third party for $135 million. Divestitures In the first quarter of 2013, proceeds from divestitures of $361 million and net gains on divestitures of $144 million were primarily related to the Company's divestiture of its interests in a soda ash joint venture.

Acquisitions and Divestitures

3 Months Ended

Mar. 31, 2013

3. Acquisitions and Divestitures

Acquisitions In March 2013, Western Gas Partners, LP (WES), a consolidated subsidiary of the Company, acquired a 33.75% interest in gas-gathering systems located in the Marcellus shale in north-central Pennsylvania from a third party for $135 million.

Divestitures In the first quarter of 2013, proceeds from divestitures of $361 million and net gains on divestitures of $144 million were primarily related to the Company's divestiture of its interests in a soda ash joint venture.