Computations of Profit Per Share (Details) (USD $) In Millions, except Share data	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010
Computations of Profit Per Share
Profit for the period (A) (in millions of dollars)	$ 1,141	[1]	$ 792	[1]	$ 3,381	[1]	$ 1,732	[1]
Weighted-average common shares outstanding (millions) -
Weighted-average number of common shares outstanding (B) (in shares)	646,600,000		632,600,000		644,300,000		629,600,000
Shares issuable on exercise of stock awards, net of shares assumed to be purchased out of proceeds at average market price (in shares)	19,400,000		19,000,000		21,800,000		17,400,000
Average common shares outstanding for fully diluted computation (C) (in shares)	666,000,000	[2]	651,600,000	[2]	666,100,000	[2]	647,000,000	[2]
Profit (loss) per share of common stock:
Assuming no dilution (A/B) (in dollars per share)	$ 1.76		$ 1.25		$ 5.25		$ 2.75
Assuming full dilution (A/C) (in dollars per share)	$ 1.71	[2]	$ 1.22	[2]	$ 5.08	[2]	$ 2.68	[2]
Common shares under SARs and stock options not included in the computation of diluted earnings per share (in shares)	2,904,815		4,853,298		2,904,815		21,652,360

[1] Profit (loss) attributable to common stockholders.

[2] Diluted by assumed exercise of stock-based compensation awards using the treasury stock method.