Earnings Per Share of Common Stock - Computation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Weighted-average number of shares on which earnings per share calculations are based
Weighted-average shares outstanding during period (in shares)	889,435,166	886,273,682	888,702,256	887,927,612
Add - Incremental shares under stock-based compensation plans (in shares)	4,290,365	3,281,570	5,015,390	3,327,015
Add - Incremental shares associated with contingently issuable shares (in shares)	1,213,549	1,276,549	1,271,513	1,116,537
Assuming dilution (in shares)	894,939,080	890,831,801	894,989,159	892,371,164
Net income on which basic earnings per share is calculated
Income from continuing operations	$ 1,362	$ 2,499	$ 2,538	$ 4,093
Income/(loss) from discontinued operations, net of tax	(1)	(1)	(2)	(4)
Net income on which basic earnings per share is calculated	1,361	2,498	2,536	4,089
Net income on which diluted earnings per share is calculated
Income from continuing operations	1,362	2,499	2,538	4,093
Net income applicable to contingently issuable shares		0	(2)	0
Income from continuing operations on which diluted earnings per share is calculated	1,362	2,500	2,536	4,093
Income/(loss) from discontinued operations, net of tax, on which basic and diluted earnings per share is calculated	(1)	(1)	(2)	(4)
Net income on which diluted earnings per share is calculated	$ 1,361	$ 2,499	$ 2,534	$ 4,090
Assuming dilution
Continuing operations (in dollars per share)	$ 1.52	$ 2.81	$ 2.83	$ 4.58
Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00
Total (in dollars per share)	1.52	2.81	2.83	4.58
Basic
Continuing operations (in dollars per share)	1.53	2.82	2.85	4.61
Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00
Total (in dollars per share)	$ 1.53	$ 2.82	$ 2.85	$ 4.61