Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share Details [Abstract]
Net income	$ 1,798	$ 1,132	$ 3,139	$ 2,606
Weighted-Average Number Of Shares Outstanding
Basic	658.5	677.7	663.1	681.0
Dilutive effect of stock options	0.8	0.7	0.8	0.8
Dilutive effect of retention shares and units	0.8	0.8	0.8	0.9
Diluted	660.1	679.2	664.7	682.7
Earnings per share - basic	$ 2.73	$ 1.67	$ 4.73	$ 3.83
Earnings per share - diluted	$ 2.72	$ 1.67	$ 4.72	$ 3.82
Stock options excluded as their inclusion would be anti-dilutive	0.4	1.0	0.3	0.8