Consolidated Statements of Changes in Equity - USD ($)	Total	Series D Preferred Stock	Series E Preferred Stock	Series F Preferred Stock	Series G Preferred Stock	Series H Preferred Stock	Preferred Stock	Common Stock	Capital Surplus	Retained Earnings	Retained Earnings Series D Preferred Stock	Retained Earnings Series E Preferred Stock	Retained Earnings Series F Preferred Stock	Retained Earnings Series G Preferred Stock	Retained Earnings Series H Preferred Stock	Treasury Stock, at Cost	Accumulated Other Comprehensive Income (Loss)
Beginning balance, Preferred Shares (in shares) at Dec. 31, 2021							1,396,000
Beginning balance, Common Shares (in shares) at Dec. 31, 2021								928,850,000
Beginning balance at Dec. 31, 2021	$ 17,423,000,000						$ 1,900,000,000	$ 1,257,000,000	$ 6,278,000,000	$ 14,553,000,000						$ (5,979,000,000)	$ (586,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	981,000,000									981,000,000
Other comprehensive income (loss)	(3,580,000,000)																(3,580,000,000)
Deferred compensation	(6,000,000)								(6,000,000)
Cash dividends declared
Cash dividends declared on common shares	(364,000,000)									(364,000,000)
Cash dividends declared on preferred stock		$ (12,000,000)	$ (16,000,000)	$ (12,000,000)	$ (12,000,000)						$ (12,000,000)	$ (16,000,000)	$ (12,000,000)	$ (12,000,000)
Employee equity compensation program Common Share repurchases (in shares)								(1,731,000)
Employee equity compensation program Common Share repurchases	(44,000,000)															(44,000,000)
Common shares reissued (returned) for stock options and other employee benefit plans (in shares)								5,524,000
Common shares reissued (returned) for stock options and other employee benefit plans	69,000,000								(31,000,000)							100,000,000
Ending balance, Preferred Shares (in shares) at Jun. 30, 2022							1,396,000
Ending balance, Common Shares (in shares) at Jun. 30, 2022								932,643,000
Ending balance at Jun. 30, 2022	14,427,000,000						$ 1,900,000,000	$ 1,257,000,000	6,241,000,000	15,118,000,000						(5,923,000,000)	(4,166,000,000)
Beginning balance, Preferred Shares (in shares) at Mar. 31, 2022							1,396,000
Beginning balance, Common Shares (in shares) at Mar. 31, 2022								932,398,000
Beginning balance at Mar. 31, 2022	15,308,000,000						$ 1,900,000,000	$ 1,257,000,000	6,214,000,000	14,793,000,000						(5,927,000,000)	(2,929,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	533,000,000									533,000,000
Other comprehensive income (loss)	(1,237,000,000)																(1,237,000,000)
Deferred compensation	0
Cash dividends declared
Cash dividends declared on common shares	(182,000,000)									(182,000,000)
Cash dividends declared on preferred stock		(6,000,000)	(8,000,000)	(6,000,000)	(6,000,000)						(6,000,000)	(8,000,000)	(6,000,000)	(6,000,000)
Employee equity compensation program Common Share repurchases (in shares)								(24,000)
Employee equity compensation program Common Share repurchases	0															0
Common shares reissued (returned) for stock options and other employee benefit plans (in shares)								269,000
Common shares reissued (returned) for stock options and other employee benefit plans	31,000,000								27,000,000							4,000,000
Ending balance, Preferred Shares (in shares) at Jun. 30, 2022							1,396,000
Ending balance, Common Shares (in shares) at Jun. 30, 2022								932,643,000
Ending balance at Jun. 30, 2022	14,427,000,000						$ 1,900,000,000	$ 1,257,000,000	6,241,000,000	15,118,000,000						(5,923,000,000)	(4,166,000,000)
Beginning balance, Preferred Shares (in shares) at Dec. 31, 2022							1,996,000
Beginning balance, Common Shares (in shares) at Dec. 31, 2022								933,325,000
Beginning balance at Dec. 31, 2022	13,454,000,000						$ 2,500,000,000	$ 1,257,000,000	6,286,000,000	15,616,000,000						(5,910,000,000)	(6,295,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	599,000,000									599,000,000
Other comprehensive income (loss)	251,000,000																251,000,000
Deferred compensation	(5,000,000)								(5,000,000)
Cash dividends declared
Cash dividends declared on common shares	(384,000,000)									(384,000,000)
Cash dividends declared on preferred stock		$ (13,000,000)	$ (15,000,000)	$ (12,000,000)	$ (13,000,000)	$ (19,000,000)					(13,000,000)	(15,000,000)	(12,000,000)	(13,000,000)	$ (19,000,000)
Open market Common Share repurchases (in shares)								(2,550,000)
Open market Common Share repurchases	(38,000,000)															(38,000,000)
Employee equity compensation program Common Share repurchases (in shares)								(1,821,000)
Employee equity compensation program Common Share repurchases	(34,000,000)															(34,000,000)
Common shares reissued (returned) for stock options and other employee benefit plans (in shares)								6,779,000
Common shares reissued (returned) for stock options and other employee benefit plans	73,000,000								(50,000,000)							123,000,000
Ending balance, Preferred Shares (in shares) at Jun. 30, 2023		21,000	500,000	425,000	450,000	600,000	1,996,000
Ending balance, Common Shares (in shares) at Jun. 30, 2023								935,733,000
Ending balance at Jun. 30, 2023	13,844,000,000						$ 2,500,000,000	$ 1,257,000,000	6,231,000,000	15,759,000,000						(5,859,000,000)	(6,044,000,000)
Beginning balance, Preferred Shares (in shares) at Mar. 31, 2023							1,996,000
Beginning balance, Common Shares (in shares) at Mar. 31, 2023								935,229,000
Beginning balance at Mar. 31, 2023	14,322,000,000						$ 2,500,000,000	$ 1,257,000,000	6,207,000,000	15,700,000,000						(5,868,000,000)	(5,474,000,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	287,000,000									287,000,000
Other comprehensive income (loss)	(570,000,000)																(570,000,000)
Deferred compensation	1,000,000								1,000,000
Cash dividends declared
Cash dividends declared on common shares	(192,000,000)									(192,000,000)
Cash dividends declared on preferred stock		$ (6,000,000)	$ (7,000,000)	$ (6,000,000)	$ (7,000,000)	$ (10,000,000)					$ (6,000,000)	$ (7,000,000)	$ (6,000,000)	$ (7,000,000)	$ (10,000,000)
Open market Common Share repurchases	0
Employee equity compensation program Common Share repurchases (in shares)								(38,000)
Employee equity compensation program Common Share repurchases	0															0
Common shares reissued (returned) for stock options and other employee benefit plans (in shares)								542,000
Common shares reissued (returned) for stock options and other employee benefit plans	32,000,000								23,000,000							9,000,000
Ending balance, Preferred Shares (in shares) at Jun. 30, 2023		21,000	500,000	425,000	450,000	600,000	1,996,000
Ending balance, Common Shares (in shares) at Jun. 30, 2023								935,733,000
Ending balance at Jun. 30, 2023	$ 13,844,000,000						$ 2,500,000,000	$ 1,257,000,000	$ 6,231,000,000	$ 15,759,000,000						$ (5,859,000,000)	$ (6,044,000,000)