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
Earnings Per Share Reconciliation [Abstract]
Net income	$ 3,662	$ 2,697	$ 2,622
Participating securities — allocated income	(27)	(19)	(19)
Net income available to common shareholders -- basic	3,635	2,678	2,603
Net income available to common shareholders -- diluted	$ 3,635	$ 2,678	$ 2,603
Weighted average shares outstanding, basic (in shares)	248.5	253.5	260.0
Weighted average effects of dilutive securities - stock options and performance shares (in shares)	2.3	1.1	2.3
Weighted average shares outstanding, diluted (in shares)	250.8	254.6	262.3
Net income per common share, basic (in dollars per share)	$ 14.63	$ 10.56	$ 10.01
Net income per common share, diluted (in dollars per share)	$ 14.49	$ 10.52	$ 9.92