Accounting For Certain Long-Lived Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Impaired Long-Lived Assets Held and Used [Line Items]
Amortization and impairments of unproved oil and gas properties including capitalized interest	$ 115	$ 228	$ 197
United States [Member]
Schedule of Impaired Long-Lived Assets Held and Used [Line Items]
Pretax impairment charges on proved oil and gas properties, other property, plant and equipment and other assets	73	171	403
Canada [Member]
Schedule of Impaired Long-Lived Assets Held and Used [Line Items]
Pretax impairment charges on proved oil and gas properties, other property, plant and equipment and other assets	76	872	428
Trinidad [Member]
Schedule of Impaired Long-Lived Assets Held and Used [Line Items]
Pretax impairment charges on proved oil and gas properties, other property, plant and equipment and other assets	14
Other International [Member]
Schedule of Impaired Long-Lived Assets Held and Used [Line Items]
Pretax impairment charges on proved oil and gas properties, other property, plant and equipment and other assets	$ 9		$ 3