Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total		Common Stock - Nonvoting [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock, at cost [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Dec. 31, 2019	$ 21,745		$ 0	$ 2,793	$ 15	$ 4,656	$ 19,960	$ (5,767)	$ 88
Beginning balance (shares) at Dec. 31, 2019			0		1,488
Increase (Decrease) in Stockholders' Equity
Net income	1,466	[1]					1,466
Other comprehensive income (loss), net of tax	5,523								5,523
Issuance of preferred stock, net	2,470			2,470
Dividends declared on preferred stock	(81)						(81)
Dividends declared on common stock	(466)						(466)
Stock option exercises and other	29					(10)		39
Share-based compensation	91					91
Other	38					23	(3)	18
Ending balance (shares) at Jun. 30, 2020			0		1,488
Ending balance at Jun. 30, 2020	30,815		$ 0	5,263	$ 15	4,760	20,876	(5,710)	5,611
Beginning balance at Mar. 31, 2020	26,270		$ 0	2,793	$ 15	4,714	20,487	(5,734)	3,995
Beginning balance (shares) at Mar. 31, 2020			0		1,488
Increase (Decrease) in Stockholders' Equity
Net income	671	[2]					671
Other comprehensive income (loss), net of tax	1,616								1,616
Issuance of preferred stock, net	2,470			2,470
Dividends declared on preferred stock	(47)						(47)
Dividends declared on common stock	(233)						(233)
Stock option exercises and other	6					(2)		8
Share-based compensation	35					35
Other	27					13	(2)	16
Ending balance (shares) at Jun. 30, 2020			0		1,488
Ending balance at Jun. 30, 2020	30,815		$ 0	5,263	$ 15	4,760	20,876	(5,710)	5,611
Beginning balance at Dec. 31, 2020	56,060		$ 1	7,733	$ 20	26,515	21,975	(5,578)	5,394
Beginning balance (shares) at Dec. 31, 2020			79		1,995
Increase (Decrease) in Stockholders' Equity
Net income	2,749	[2]	$ 115				2,749
Other comprehensive income (loss), net of tax	(2,986)								(2,986)
Issuance of preferred stock, net	2,806			2,806
Redemption of preferred stock	(600)			(585)			(15)
Dividends declared on preferred stock	(218)						(218)
Dividends declared on common stock	(682)						(682)
Stock option exercises and other	144					8		136
Share-based compensation	145					145
Other	32					40		(8)
Ending balance (shares) at Jun. 30, 2021			79		1,995
Ending balance at Jun. 30, 2021	57,450		$ 1	9,954	$ 20	26,708	23,809	(5,450)	2,408
Beginning balance at Mar. 31, 2021	55,594		$ 1	10,539	$ 20	26,629	23,029	(5,502)	878
Beginning balance (shares) at Mar. 31, 2021			79		1,995
Increase (Decrease) in Stockholders' Equity
Net income	1,265	[2]	$ 53				1,265
Other comprehensive income (loss), net of tax	1,530								1,530
Redemption of preferred stock	(600)			(585)			(15)
Dividends declared on preferred stock	(128)						(128)
Dividends declared on common stock	(342)						(342)
Stock option exercises and other	47							47
Share-based compensation	47					47
Other	37					32		5
Ending balance (shares) at Jun. 30, 2021			79		1,995
Ending balance at Jun. 30, 2021	$ 57,450		$ 1	$ 9,954	$ 20	$ 26,708	$ 23,809	$ (5,450)	$ 2,408

[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.