Earnings Per Share (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]
Net income	$ 779	$ 891	$ 1,513	$ 1,844
Weighted-average shares outstanding	337,846,228	341,047,290	338,353,260	340,913,450
Share-based compensation plans	3,286,359	3,053,975	3,267,499	3,120,263
Adjusted weighted-average shares outstanding and assumed conversions	341,132,587	344,101,265	341,620,759	344,033,713
Basic earnings per share (US$ per share)	$ 2.30	$ 2.61	$ 4.47	$ 5.41
Diluted earnings per share (US$ per share)	$ 2.28	$ 2.59	$ 4.43	$ 5.36
Potential anti-dilutive share conversions	1,778,040	1,811,030	1,220,731	1,231,105