Divestitures and Assets Held for Sale - Assets Held for Sale (Details) (Assets Held For Sale [Member], Oil and Gas Exploration and Production Reporting Segment [Member], USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
Long Lived Assets Held-for-sale [Line Items]
Current assets associated with assets held for sale	$ 181
Long-term assets associated with assets held for sale	452
Current liabilities associated with assets held for sale	66
Long-term liabilities associated with assets held for sale	45
Chinese Subsidiary [Member]
Long Lived Assets Held-for-sale [Line Items]
Expected proceeds from divestiture	$ 1,075