Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net income (loss)	$ 2,265	$ (331)	$ 4,565	$ (79)
Weighted-average shares outstanding	445,094,678	451,402,807	447,802,079	451,635,733
Share-based compensation plans	2,857,242	1,395,951	2,900,440	2,044,144
Weighted-average shares outstanding and assumed conversions	447,951,920	451,402,807	450,702,519	451,635,733
Basic earnings (loss) per share (US$ per share)	$ 5.09	$ (0.73)	$ 10.20	$ (0.17)
Diluted earnings (loss) per share (US$ per share)	$ 5.06	$ (0.73)	$ 10.13	$ (0.17)
Potential anti-dilutive share conversions	1,777,555	8,378,447	1,879,882	6,583,319