Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net income	$ 1,150	$ 1,294	$ 2,190	$ 2,376
Weighted-average shares outstanding	457,224,455	465,276,597	458,010,447	465,488,724
Share-based compensation plans	2,945,237	3,103,727	2,863,109	3,489,013
Weighted-average shares outstanding and assumed conversions	460,169,692	468,380,324	460,873,556	468,977,737
Basic earnings per share (US$ per share)	$ 2.52	$ 2.78	$ 4.78	$ 5.10
Diluted earnings per share (US$ per share)	$ 2.50	$ 2.76	$ 4.75	$ 5.07
Potential anti-dilutive share conversions	2,660,925	3,814,491	5,037,959	3,305,735