Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income	$ 2,300	$ 252
Weighted-average shares outstanding	450,539,568	451,868,658
Share-based compensation plans	2,795,971	2,651,610
Weighted-average shares outstanding and assumed conversions	453,335,539	454,520,268
Basic earnings per share (US$ per share)	$ 5.10	$ 0.56
Diluted earnings per share (US$ per share)	$ 5.07	$ 0.55
Potential anti-dilutive share conversions	1,952,612	3,154,406