Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 1,194	$ 1,091	$ 1,115	$ 3,281
Weighted-average shares outstanding	451,794,046	454,975,143	451,683,093	456,987,560
Share-based compensation plans	1,471,434	3,175,226	1,894,699	2,937,026
Weighted-average shares outstanding and assumed conversions	453,265,480	458,150,369	453,577,792	459,924,586
Basic earnings per share (US$ per share)	$ 2.64	$ 2.40	$ 2.47	$ 7.18
Diluted earnings per share (US$ per share)	$ 2.63	$ 2.38	$ 2.46	$ 7.13
Potential anti-dilutive share conversions	7,053,316	575,039	6,767,727	3,874,310