CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (unaudited) - USD ($) $ in Millions	Total	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	Preferred Stock	Capital Surplus	Retained Earnings	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) Income	Treasury Stock
Balance at Dec. 31, 2020	$ 23,111							$ 2,051	$ 2,116	$ 3,635	$ 18,384							$ 2,601	$ (5,676)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	2,107										2,107
Other comprehensive income (loss), net of tax	(964)																	(964)
Cash dividends declared:
Common stock	(597)										(597)
Preferred stock		$ (15)	$ (22)	$ (8)	$ (9)	$ (12)	$ (9)					$ (15)	$ (22)	$ (8)	$ (9)	$ (12)	$ (9)
Shares acquired for treasury	(1,077)																		(1,077)
Impact of stock transactions under stock compensation plans, net	20									(24)									44
Other	(1)										(2)								1
Balance at Sep. 30, 2021	22,524							2,051	2,116	3,611	19,817							1,637	(6,708)
Balance at Jun. 30, 2021	22,926							2,051	2,116	3,602	19,343							1,974	(6,160)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	704										704
Other comprehensive income (loss), net of tax	(337)																	(337)
Cash dividends declared:
Common stock	(210)										(210)
Preferred stock			(7)	(3)	(3)	(4)	(3)						(7)	(3)	(3)	(4)	(3)
Shares acquired for treasury	(550)																		(550)
Impact of stock transactions under stock compensation plans, net	11									9									2
Balance at Sep. 30, 2021	22,524							2,051	2,116	3,611	19,817							1,637	(6,708)
Balance at Dec. 31, 2021	22,210							2,051	2,116	3,624	20,236							1,207	(7,024)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,709										1,709
Other comprehensive income (loss), net of tax	(6,513)																	(6,513)
Cash dividends declared:
Common stock	(648)										(648)
Preferred stock		$ (15)	(23)	(10)	(9)	(12)	(9)					$ (15)	(23)	(10)	(9)	(12)	(9)
Impact of stock transactions under stock compensation plans, net	56									36									20
Balance at Sep. 30, 2022	16,736							2,051	2,116	3,660	21,219							(5,306)	(7,004)
Balance at Jun. 30, 2022	18,970							2,051	2,116	3,636	20,818							(2,644)	(7,007)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	653										653
Other comprehensive income (loss), net of tax	(2,662)																	(2,662)
Cash dividends declared:
Common stock	(230)										(230)
Preferred stock			$ (8)	$ (4)	$ (3)	$ (4)	$ (3)						$ (8)	$ (4)	$ (3)	$ (4)	$ (3)
Impact of stock transactions under stock compensation plans, net	27									24									3
Balance at Sep. 30, 2022	$ 16,736							$ 2,051	$ 2,116	$ 3,660	$ 21,219							$ (5,306)	$ (7,004)