Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Basic Earnings per Common Share
Income from continuing operations	$ 6,427	$ 6,732	$ 8,084
Less: cumulative dividends on subsidiary preferred stock	(180)	(151)	(98)
Income from continuing operations attributable to common stockholders	6,247	6,581	7,986
Loss from discontinued operations, net of tax	0	0	70
Net income attributable to common stockholders	$ 6,247	$ 6,581	$ 7,916
Weighted-average common shares outstanding - basic (in shares)	1,433	1,424	1,411
Basic earnings per common share – continuing operations (in dollars per share)	$ 4.36	$ 4.62	$ 5.66
Basic loss per common share – discontinued operations (in dollars per share)	0	0	0.05
Basic earnings per common share (in dollars per share)	$ 4.36	$ 4.62	$ 5.61
Diluted earnings per share
Income from continuing operations attributable to common stockholders – diluted	$ 6,247	$ 6,581	$ 7,986
Loss from discontinued operations, net of tax – diluted	0	0	70
Net income attributable to common stockholders – diluted	$ 6,247	$ 6,581	$ 7,916
Weighted-average common shares outstanding - basic (in shares)	1,433	1,424	1,411
Dilutive effect of warrants and awards under stock incentive plans (in shares)	9	15	20
Weighted-average common shares outstanding – diluted (in shares)	1,442	1,439	1,431
Diluted earnings per common share – continuing operations (in dollars per share)	$ 4.33	$ 4.57	$ 5.58
Diluted loss per common share – discontinued operations (in dollars per share)	0	0	0.05
Diluted earnings per common share (in dollars per share)	$ 4.33	$ 4.57	$ 5.53
Potentially dilutive securities (in shares)	7	7	9

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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- Definition

Per basic share amount, after tax, of income (loss) from the day-to-day business activities of the discontinued operation.

+ References

No definition available.