Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total		Common Stock	Nonvoting Common Stock	Preferred Stock	Common Stock	Common Stock Common Stock	Common Stock Nonvoting Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock, at cost	Treasury Stock, at cost Common Stock	Treasury Stock, at cost Nonvoting Common Stock	Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period at Dec. 31, 2020	$ 56,060.0				$ 7,733.0		$ 20.0	$ 1.0	$ 26,515.0	$ 21,975.0	$ (5,578.0)			$ 5,394.0
Beginning balance (in shares) at Dec. 31, 2020							1,995	79
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	5,855.0	[1]	$ 5,610.0	$ 245.0						5,855.0
Other comprehensive income (loss), net of tax	(6,503.0)													(6,503.0)
Issuance of preferred stock, net	2,806.0				2,806.0
Redemption of preferred stock	(600.0)				(585.0)					(15.0)
Dividends declared on preferred stock	(456.1)									(456.0)
Dividends declared on common stock	(1,367.0)									(1,367.0)
Stock option exercises and other	221.0								(84.0)		305.0
Share-based compensation	229.0								229.0
Other	16.0								81.0		(65.0)
Balance at end of period at Dec. 31, 2021	56,261.0				9,954.0		$ 20.0	$ 1.0	26,741.0	25,992.0	(5,338.0)			(1,109.0)
Ending balance (in shares) at Dec. 31, 2021							1,995	79
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	7,183.0	[1]	6,926.0	257.0						7,183.0
Other comprehensive income (loss), net of tax	(21,512.0)													(21,512.0)
Issuance of preferred stock, net	740.0				740.0
Redemption of preferred stock	(1,000.0)				(988.0)					(12.0)
Dividends declared on preferred stock	(504.6)									(505.0)
Dividends declared on common stock	(1,592.0)									(1,592.0)
Repurchase of stock (in shares)						32	15	15
Repurchase of stock			(2,435.0)	(1,000.0)		$ (2,400.0)						$ (2,435.0)	$ (1,000.0)
Conversion of nonvoting common stock to common stock (in shares)							13	(13)
Stock option exercises and other	64.0								(124.0)		188.0
Share-based compensation	348.0								348.0
Other	56.0								110.0		(54.0)
Balance at end of period at Dec. 31, 2022	36,608.0	[2]			9,706.0		$ 20.0	$ 1.0	27,075.0	31,066.0	(8,639.0)			(22,621.0)
Ending balance (in shares) at Dec. 31, 2022							2,023	51
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	5,067.0	[1]	$ 4,925.0	$ 142.0						5,067.0
Other comprehensive income (loss), net of tax	4,490.0													4,490.0
Redemption and repurchase of preferred stock, inclusive of tax	(471.0)				(515.0)					44.0
Dividends declared on preferred stock	(438.4)									(438.0)
Dividends declared on common stock	(1,838.0)									(1,838.0)
Repurchase of stock (in shares)						37
Repurchase of stock	(2,866.0)					$ (2,800.0)					(2,866.0)
Stock option exercises and other	49.0								(145.0)		194.0
Share-based compensation	294.0								294.0
Other	63.0								106.0		(43.0)
Balance at end of period at Dec. 31, 2023	$ 40,958.0	[2]			$ 9,191.0		$ 20.0	$ 1.0	$ 27,330.0	$ 33,901.0	$ (11,354.0)			$ (18,131.0)
Ending balance (in shares) at Dec. 31, 2023							2,023	51

[1] Certain prior year amounts have been reclassified to conform to the current year presentation. See Note 1 for additional information.

[2] Certain prior year amounts have been reclassified to conform to the current year presentation. See Note 1 for additional information.