Acquisitions and Divestitures	9 Months Ended
Sep. 30, 2013
Disclosure Text Block [Abstract]
Acquisitions and Divestitures	3. Acquisitions and Divestitures Acquisitions Anadarko and Western Gas Partners, LP (WES), a consolidated subsidiary of the Company, made several unrelated acquisitions during the nine months ended September 30, 2013. In March 2013, WES acquired a 33.75% interest in gas-gathering systems located in the Marcellus shale in north-central Pennsylvania for $135 million. In June 2013, WES acquired a 25% interest in a joint venture formed to design, construct, and own two fractionators located in Mont Belvieu, Texas for $78 million. In August 2013, Anadarko acquired certain oil and gas properties and related assets in the Moxa area of Wyoming for $310 million, including $306 million that represents the fair value of the oil and gas properties acquired. In September 2013, WES acquired an intrastate pipeline in southwestern Wyoming for $28 million. Divestitures For the nine months ended September 30, 2013, proceeds from divestitures of $451 million and net gains on divestitures of $165 million were primarily related to the Company’s divestiture of its interests in a soda ash joint venture during the first quarter of 2013. In August 2013, the Company entered into a definitive agreement to sell a 10% working interest in Mozambique’s Offshore Area 1 for $2.64 billion. The transaction is subject to governmental approvals and other customary closing conditions, and is expected to close in late 2013 or early 2014.

3. Acquisitions and Divestitures

Acquisitions Anadarko and Western Gas Partners, LP (WES), a consolidated subsidiary of the Company, made several unrelated acquisitions during the nine months ended September 30, 2013. In March 2013, WES acquired a 33.75% interest in gas-gathering systems located in the Marcellus shale in north-central Pennsylvania for $135 million. In June 2013, WES acquired a 25% interest in a joint venture formed to design, construct, and own two fractionators located in Mont Belvieu, Texas for $78 million. In August 2013, Anadarko acquired certain oil and gas properties and related assets in the Moxa area of Wyoming for $310 million, including $306 million that represents the fair value of the oil and gas properties acquired. In September 2013, WES acquired an intrastate pipeline in southwestern Wyoming for $28 million.

Divestitures For the nine months ended September 30, 2013, proceeds from divestitures of $451 million and net gains on divestitures of $165 million were primarily related to the Company’s divestiture of its interests in a soda ash joint venture during the first quarter of 2013. In August 2013, the Company entered into a definitive agreement to sell a 10% working interest in Mozambique’s Offshore Area 1 for $2.64 billion. The transaction is subject to governmental approvals and other customary closing conditions, and is expected to close in late 2013 or early 2014.