Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net income	$ 2,760	$ 1,534	$ 1,893
Denominator:
Basic: Weighted-average common shares outstanding	117.3	123.8	134.1
Effect of potentially dilutive nonqualified stock options and other share-based awards (in shares)	2.7	1.9	1.9
Diluted: Weighted-average common shares outstanding	120.0	125.7	136.0
Earnings Per Share, Basic:
Net income (in dollars per basic share)	$ 23.53	$ 12.39	$ 14.12
Earnings Per Share, Diluted:
Net income (in dollars per diluted share)	$ 23.00	$ 12.20	$ 13.92
Options excluded from earnings per share calculation due to their anti-dilutive effect (in shares)	0.0	0.0	1.0