Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share Details [Abstract]
Net income	$ 1,673	$ 1,363	$ 4,812	$ 3,969
Weighted-Average Number Of Shares Outstanding
Basic	648.7	675.0	658.3	679.0
Dilutive effect of stock options	0.8	0.9	0.8	0.8
Dilutive effect of retention shares and units	0.8	0.9	0.8	0.9
Diluted	650.3	676.8	659.9	680.7
Earnings per share - basic	$ 2.58	$ 2.02	$ 7.31	$ 5.85
Earnings per share - diluted	$ 2.57	$ 2.01	$ 7.29	$ 5.83
Stock options excluded as their inclusion would be anti-dilutive	0.4	0.5	0.3	0.7