Profit Per Share (Details) (USD $)	1 Months Ended	3 Months Ended					9 Months Ended				80 Months Ended
	Feb. 28, 2007	Sep. 30, 2013		Jun. 30, 2013	Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013
Earnings Per Share [Abstract]
Profit for the period (A) (in dollars)		$ 946,000,000	[1]		$ 1,699,000,000	[1]	$ 2,786,000,000	[1]	$ 4,984,000,000	[1]
Weighted-average common shares outstanding:
Weighted-average number of common shares outstanding (B) (in shares)		639,300,000			653,600,000		647,600,000		652,000,000
Shares issuable on exercise of stock awards, net of shares assumed to be purchased out of proceeds at average market price (in shares)		12,600,000			15,100,000		13,700,000		17,700,000
Average common shares outstanding for fully diluted computation (C) (in shares)		651,900,000	[2]		668,700,000	[2]	661,300,000	[2]	669,700,000	[2]
Profit (loss) per share of common stock:
Assuming no dilution (A/B) (in dollars per share)		$ 1.48			$ 2.60		$ 4.30		$ 7.64
Assuming full dilution (A/C) (in dollars per share)		$ 1.45	[2]		$ 2.54	[2]	$ 4.21	[2]	$ 7.44	[2]
Shares outstanding as of September 30		636,400,000			653,900,000		636,400,000		653,900,000		636,400,000
Common shares under SARs and stock options not included in the computation of diluted earnings per share (in shares)		10,285,409			6,073,271		10,191,424		6,073,271
Common stock repurchase
Stock Repurchase Program, Authorized Amount	7,500,000,000
Common shares repurchased (in shares)		11,942,737		11,542,106			23,484,843		0
Payments for repurchase of common stock		1,000,000,000		1,000,000,000			2,000,000,000		0
Stock repurchase program, amount of authorized repurchase spent to date											$ 5,800,000,000

[1] 1 Profit attributable to common stockholders.

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