Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income	$ 1,091	$ 1,231	$ 3,281	$ 3,607
Weighted-average shares outstanding	454,975,143	462,981,973	456,987,560	464,644,013
Share-based compensation plans	3,175,226	3,034,525	2,937,026	3,360,511
Weighted-average shares outstanding and assumed conversions	458,150,369	466,016,498	459,924,586	468,004,524
Basic earnings per share (US$ per share)	$ 2.40	$ 2.66	$ 7.18	$ 7.76
Diluted earnings per share (US$ per share)	$ 2.38	$ 2.64	$ 7.13	$ 7.71
Potential anti-dilutive share conversions	575,039	3,763,844	3,874,310	3,467,000