Contingencies - Algeria Exceptional Profits Tax Settlement (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended						3 Months Ended	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Maximum [Member]	Mar. 31, 2012 Algeria Exceptional Profits Tax Settlement [Member]	Dec. 31, 2012 Algeria Exceptional Profits Tax Settlement [Member]	Dec. 31, 2012 Algeria Exceptional Profits Tax Settlement [Member] Oil and Gas Exploration and Production Reporting Segment [Member]
Commitments and Contingencies [Line Items]
Algeria exceptional profits tax settlement	$ 730						$ 1,700		$ 730
(Increase) decrease in accounts payable and accrued expenses	476		(284)	157			62
Algeria exceptional profits tax settlement	$ 1,797	[1]						$ 1,797
Length of each exploitation license	25 years
Exploitation license, expiration date					Dec. 31, 2022	Dec. 31, 2036

[1] In the first quarter of 2012, the Company revised the definition of Adjusted EBITDAX to exclude Algeria exceptional profits tax settlement, Tronox-related contingent loss, and realized (gains) losses on other derivatives, net. Prior periods have been adjusted to reflect this change.