Earnings Per Common Share (EPS) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2023		Sep. 30, 2022		Sep. 30, 2023		Sep. 30, 2022
Basic and diluted:
Net income	$ 2,451		$ 1,879		$ 6,441		$ 5,942
Preferred dividends	(14)		(14)		(43)		(43)
Net income available to common shareholders	2,437		1,865		6,398		5,899
Earnings allocated to participating share awards	(19)		(14)		(50)		(45)
Net income attributable to common shareholders	$ 2,418		$ 1,851		$ 6,348		$ 5,854
Denominator:
Basic: Weighted-average common stock (in shares)	732.0		748.0		738.0		752.0
Add: Weighted-average stock options (in shares)	1.0		1.0		1.0		1.0
Diluted (in shares)	733.0		749.0		739.0		753.0
Basic EPS (in dollars per share)	$ 3.30	[1]	$ 2.47	[1]	$ 8.60	[2]	$ 7.78	[2]
Diluted EPS (in dollars per share)	$ 3.30	[1]	$ 2.47	[1]	$ 8.59	[2]	$ 7.77	[2]
Stock options
Denominator:
The dilutive effect of securities excluded from the calculation of earnings per share (in shares)	1.4		0.3		1.4		0.2

[1] Represents net income less (i) earnings allocated to participating share awards of $19 million and $14 million for the three months ended September 30, 2023 and 2022, respectively, and (ii) dividends on preferred shares of $14 million for both the three months ended September 30, 2023 and 2022.

[2] Represents net income less (i) earnings allocated to participating share awards of $50 million and $45 million for the nine months ended September 30, 2023 and 2022, respectively, and (ii) dividends on preferred shares of $43 million for both the nine months ended September 30, 2023 and 2022.