Earnings Per Common Share (EPS) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022
Basic and diluted:
Net income		$ 1,816	$ 2,099
Preferred dividends		(14)	(14)
Net income available to common shareholders		1,802	2,085
Earnings allocated to participating share awards		(14)	(16)
Net income attributable to common shareholders		$ 1,788	$ 2,069
Denominator:
Basic: Weighted-average common stock (in shares)		743.0	757.0
Add: Weighted-average stock options (in shares)		1.0	1.0
Diluted (in shares)		744.0	758.0
Basic EPS (in dollars per share)	[1]	$ 2.41	$ 2.73
Diluted EPS (in dollars per share)	[1]	$ 2.40	$ 2.73
Stock options
Denominator:
The dilutive effect of securities excluded from the calculation of earnings per share (in shares)		1.3	0.1

[1] Represents net income less (i) earnings allocated to participating share awards of $14 million and $16 million for the three months ended March 31, 2023 and 2022, respectively, and (ii) dividends on preferred shares of $14 million for both the three months ended March 31, 2023 and 2022.