Earnings Per Share (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Net income	$ 785	$ 916	$ 2,298	$ 2,760
Weighted-average shares outstanding	334,472,324	340,888,648	337,083,498	340,905,322
Share-based compensation plans	3,201,656	2,929,089	3,298,569	3,146,728
Weighted-average shares outstanding and assumed conversions	337,673,980	343,817,737	340,382,067	344,052,050
Basic earnings per share (US$ per share)	$ 2.35	$ 2.68	$ 6.82	$ 8.09
Diluted earnings per share (US$ per share)	$ 2.32	$ 2.66	$ 6.75	$ 8.02
Potential anti-dilutive share conversions	1,227,575	1,215,884	1,410,340	1,429,514