Common, Preferred and Treasury Stock - Share Activity within Common, Preferred and Treasury Stock (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Value
Beginning balance	$ 17,327	$ 22,210	$ 23,111
Shares acquired for treasury	(201)	(100)	(1,393)
Other			(1)
Ending balance	19,172	17,327	22,210
Common Stock
Value
Beginning balance	2,051	2,051	2,051
Ending balance	$ 2,051	$ 2,051	$ 2,051
Shares
Beginning balance (in shares)	923,892,581	923,892,581	923,892,581
Ending balance (in shares)	923,892,581	923,892,581	923,892,581
Preferred Stock
Value
Beginning balance	$ 2,116	$ 2,116	$ 2,116
Ending balance	$ 2,116	$ 2,116	$ 2,116
Shares
Beginning balance (in shares)	278,000	278,000	278,000
Ending balance (in shares)	278,000	278,000	278,000
Treasury Stock
Value
Beginning balance	$ (7,103)	$ (7,024)	$ (5,676)
Shares acquired for treasury	(201)	(100)	(1,393)
Impact of stock transactions under stock compensation plans, net	42	21	44
Other		0	1
Ending balance	$ (7,262)	$ (7,103)	$ (7,024)
Shares
Beginning balance (in shares)	240,506,701	241,114,917	211,132,256
Shares acquired for treasury (in shares)	5,589,996	3,079,462	35,652,079
Impact of stock transactions under stock compensation plans, net (in shares)	(3,328,926)	(3,687,834)	(5,621,878)
Other (in shares)		156	(47,540)
Ending balance (in shares)	242,767,771	240,506,701	241,114,917