CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (unaudited) - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment		Cumulative Effect, Period of Adoption, Adjusted Balance	Series H Preferred Stock	Series I Preferred Stock	Series J Preferred Stock	Series K Preferred Stock	Series L Preferred Stock	Class B, Series A Preferred Stock	Common Stock	Common Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Preferred Stock	Preferred Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Capital Surplus	Capital Surplus Cumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment		Retained Earnings Cumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings Series H Preferred Stock	Retained Earnings Series I Preferred Stock	Retained Earnings Series J Preferred Stock	Retained Earnings Series K Preferred Stock	Retained Earnings Series L Preferred Stock	Retained Earnings Class B, Series A Preferred Stock	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative Effect, Period of Adoption, Adjusted Balance	Treasury Stock	Treasury Stock Cumulative Effect, Period of Adoption, Adjusted Balance
Beginning balance at Dec. 31, 2022	$ 17,327	$ 37		$ 17,364							$ 2,051	$ 2,051	$ 2,116	$ 2,116	$ 3,684	$ 3,684	$ 21,689	$ 37		$ 21,726							$ (5,110)	$ (5,110)	$ (7,103)	$ (7,103)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	558																558
Other comprehensive income (loss), net of tax	865																										865
Cash dividends declared:
Common stock	(229)																(229)
Preferred stock						$ (7)	$ (6)	$ (3)	$ (4)	$ (3)												$ (7)	$ (6)	$ (3)	$ (4)	$ (3)
Shares acquired for treasury	(201)																												(201)
Impact of stock transactions under stock compensation plans, net	30														(2)														32
Ending balance at Mar. 31, 2023	18,364										2,051		2,116		3,682		22,032										(4,245)		(7,272)
Beginning balance at Dec. 31, 2022	17,327	37		17,364							2,051	2,051	2,116	2,116	3,684	3,684	21,689	37		21,726							(5,110)	(5,110)	(7,103)	(7,103)
Ending balance at Dec. 31, 2023	$ 19,172	$ (10)	[1]	$ 19,162							2,051	$ 2,051	2,116	$ 2,116	3,757	$ 3,757	22,997	$ (10)	[1]	$ 22,987							(4,487)	$ (4,487)	(7,262)	$ (7,262)
Cash dividends declared:
Accounting Standards Update [Extensible Enumeration]	Accounting Standard Update 2023-02 [Member]
Net Income	$ 520																520
Other comprehensive income (loss), net of tax	(401)																										(401)
Common stock	(243)																(243)
Preferred stock					$ (13)	$ (10)	$ (7)	$ (3)	$ (4)	$ (3)											$ (13)	$ (10)	$ (7)	$ (3)	$ (4)	$ (3)
Impact of stock transactions under stock compensation plans, net	20														(15)														35
Ending balance at Mar. 31, 2024	$ 19,018										$ 2,051		$ 2,116		$ 3,742		$ 23,224										$ (4,888)		$ (7,227)

[1] Related to the adoption of ASU 2023-02 as of January 1, 2024. Refer to Note 3 for additional information.