Consolidated Statements Of Changes In Shareholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Nonredeemable Preferred Stock	Common Stock	Capital Surplus	Accumulated Other Comprehensive Loss	Retained Earnings	Treasury Stock, Common
BALANCE (in shares)			139,200
BALANCE at Dec. 31, 2020	$ 8,050	$ 394	$ 1,141	$ 2,185	$ 64	$ 9,727	$ (5,461)
Net income	1,168					1,168
Other comprehensive income (loss), net of tax	(276)				(276)
Cash dividends declared on common stock	(365)					(365)
Cash dividends declared on preferred stock	(23)					(23)
Purchase of common stock	(723)			(24)		0	(699)
Purchase of common stock (in shares)			9,500
Net issuance of common stock under employee stock plans (in shares)			1,000
Net issuance of common stock under employee stock plans	25			27		13	65
Share-based compensation	41			41
BALANCE at Dec. 31, 2021	7,897	394	$ 1,141	2,175	(212)	10,494	(6,095)
BALANCE (in shares)			130,700
Net income	1,151				0	1,151
Other comprehensive income (loss), net of tax	(3,530)				(3,530)
Cash dividends declared on common stock	(356)					(356)
Cash dividends declared on preferred stock	(23)					(23)
Purchase of common stock	$ (36)			0		0	(36)
Purchase of common stock (in shares)	377		400
Net issuance of common stock under employee stock plans (in shares)			700
Net issuance of common stock under employee stock plans	$ 18			15		8	41
Share-based compensation	60			60
BALANCE at Dec. 31, 2022	5,181	394	$ 1,141	2,220	(3,742)	11,258	(6,090)
BALANCE (in shares)			131,000
Net income	881					881
Other comprehensive income (loss), net of tax	694				694
Cash dividends declared on common stock	(375)					(375)
Cash dividends declared on preferred stock						(23)
Purchase of common stock	(23)
Net issuance of common stock under employee stock plans (in shares)			900
Net issuance of common stock under employee stock plans	(4)			48		14	58
Share-based compensation	52			52
BALANCE at Dec. 31, 2023	$ 6,406	$ 394	$ 1,141	$ 2,224	$ (3,048)	$ 11,727	$ (6,032)
BALANCE (in shares)			131,900