Impairments - Table (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Impaired Long-Lived Assets Held and Used [Line Items]
Impairments of fixed assets and other	$ 546	$ 340	$ 46
Land and Building [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairments of fixed assets and other	366	248	3
Exploration and Production Equipment [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairments of fixed assets and other	71	60	0
Gas Gathering and Processing Equipment [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairments of fixed assets and other	22	6	43
Other Assets
Impaired Long-Lived Assets Held and Used [Line Items]
Impairments of fixed assets and other	$ 87	$ 26	$ 0