Consolidated Statements Of Changes In Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Nonredeemable Preferred Stock	Common Stock	Capital Surplus	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock
BALANCE (in shares) at Dec. 31, 2020			139.2
BALANCE at Dec. 31, 2020	$ 8,050	$ 394	$ 1,141	$ 2,185	$ 64	$ 9,727	$ (5,461)
Net income	678					678
Other comprehensive loss, net of tax	(184)				(184)
Cash dividends declared on common stock	(187)					(187)
Cash dividends declared on preferred stock	(11)					(11)
Purchase of common stock	(453)			(24)			(429)
Purchase of common stock (in shares)			(5.9)
Net issuance of common stock under employee stock plans	9			(27)		(5)	41
Net issuance of common stock under employee stock plans (in shares)			0.6
Share-based compensation	29			29
BALANCE at Jun. 30, 2021	7,931	394	$ 1,141	2,163	(120)	10,202	(5,849)
BALANCE (in shares) at Jun. 30, 2021			133.9
BALANCE (in shares) at Mar. 31, 2021			139.6
BALANCE at Mar. 31, 2021	8,152	394	$ 1,141	2,183	(105)	9,975	(5,436)
Net income	328					328
Other comprehensive loss, net of tax	(15)				(15)
Cash dividends declared on common stock	(92)					(92)
Cash dividends declared on preferred stock	(5)					(5)
Purchase of common stock	(450)			(24)			(426)
Purchase of common stock (in shares)			(5.8)
Net issuance of common stock under employee stock plans	6			(3)		(4)	13
Net issuance of common stock under employee stock plans (in shares)			0.1
Share-based compensation	7			7
BALANCE at Jun. 30, 2021	7,931	394	$ 1,141	2,163	(120)	10,202	(5,849)
BALANCE (in shares) at Jun. 30, 2021			133.9
BALANCE (in shares) at Dec. 31, 2021			130.7
BALANCE at Dec. 31, 2021	7,897	394	$ 1,141	2,175	(212)	10,494	(6,095)
Net income	450					450
Other comprehensive loss, net of tax	(1,742)				(1,742)
Cash dividends declared on common stock	(178)					(178)
Cash dividends declared on preferred stock	(11)					(11)
Purchase of common stock	(36)						(36)
Purchase of common stock (in shares)			(0.4)
Net issuance of common stock under employee stock plans	16			(10)		(3)	29
Net issuance of common stock under employee stock plans (in shares)			0.5
Share-based compensation	39			39
BALANCE at Jun. 30, 2022	6,435	394	$ 1,141	2,204	(1,954)	10,752	(6,102)
BALANCE (in shares) at Jun. 30, 2022			130.8
BALANCE (in shares) at Mar. 31, 2022			130.7
BALANCE at Mar. 31, 2022	7,036	394	$ 1,141	2,194	(1,173)	10,585	(6,105)
Net income	261					261
Other comprehensive loss, net of tax	(781)				(781)
Cash dividends declared on common stock	(89)					(89)
Cash dividends declared on preferred stock	(5)					(5)
Net issuance of common stock under employee stock plans	2			(1)			3
Net issuance of common stock under employee stock plans (in shares)			0.1
Share-based compensation	11			11
BALANCE at Jun. 30, 2022	$ 6,435	$ 394	$ 1,141	$ 2,204	$ (1,954)	$ 10,752	$ (6,102)
BALANCE (in shares) at Jun. 30, 2022			130.8