Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Millions	Total	Preferred Stock [Member]	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	AOCI Attributable to Parent [Member]	Share-based Payment Arrangement [Member] Treasury Stock
Beginning balance at Dec. 31, 2020				$ 4,322	$ 13,918	$ (1,192)	$ 1,170
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under incentive and stock compensation plans and other				(80)
Stock-based compensation plans expense				97
Net income	$ 1,636				1,636
Dividends declared on preferred stock	(16)				(16)
Dividends declared on common stock					(369)
Treasury stock acquired	(1,200)					(1,202)
Issuance of shares under incentive and stock compensation plans from treasury stock and other								$ 130
Net shares acquired related to employee incentive and stock compensation plans						(27)
Total other comprehensive loss							(863)
Ending balance at Sep. 30, 2021	$ 17,862	$ 334	$ 4	4,339	15,169	(2,291)	307
Preferred Stock, Shares Outstanding, Ending Balance at Sep. 30, 2021		13,800
Common Shares Outstanding, beginning of period at Dec. 31, 2020			358,489
Shares Granted or Issued, Share-based Payment Arrangement [Abstract]
Treasury stock acquired	(19,000)		(18,765)
Issuance of shares under incentive and stock compensation plans and other			2,589
Return of shares under incentive and stock compensation plans to treasury stock			(528)
Common Shares Outstanding, at end of period at Sep. 30, 2021			341,785
Shares Granted or Issued, Share-based Payment Arrangement [Abstract]
Cash dividends declared per common share	$ 1.050
Cash dividends declared per preferred share	$ 1,125
Beginning balance at Jun. 30, 2021				4,330	14,813	(1,807)	570
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under incentive and stock compensation plans and other				(9)
Stock-based compensation plans expense				18
Net income	$ 482				482
Dividends declared on preferred stock	(6)				(6)
Dividends declared on common stock					(120)
Treasury stock acquired						(511)
Issuance of shares under incentive and stock compensation plans from treasury stock and other								28
Net shares acquired related to employee incentive and stock compensation plans						(1)
Total other comprehensive loss							(263)
Ending balance at Sep. 30, 2021	$ 17,862	$ 334	$ 4	4,339	15,169	(2,291)	307
Preferred Stock, Shares Outstanding, Ending Balance at Sep. 30, 2021		13,800
Common Shares Outstanding, beginning of period at Jun. 30, 2021			348,998
Shares Granted or Issued, Share-based Payment Arrangement [Abstract]
Treasury stock acquired			(7,729)
Issuance of shares under incentive and stock compensation plans and other			532
Return of shares under incentive and stock compensation plans to treasury stock			(16)
Common Shares Outstanding, at end of period at Sep. 30, 2021			341,785
Shares Granted or Issued, Share-based Payment Arrangement [Abstract]
Cash dividends declared per common share	$ 0.350
Cash dividends declared per preferred share	$ 375.00
Beginning balance at Dec. 31, 2021	$ 17,843			3,309	15,764	(1,740)	172
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under incentive and stock compensation plans and other				(130)
Stock-based compensation plans expense				98
Net income	1,226				1,226
Dividends declared on preferred stock	(16)				(16)
Dividends declared on common stock					(376)
Treasury stock acquired	(1,200)					(1,200)
Issuance of shares under incentive and stock compensation plans from treasury stock and other								151
Net shares acquired related to employee incentive and stock compensation plans						(55)
Total other comprehensive loss							(4,586)
Ending balance at Sep. 30, 2022	$ 12,955	$ 334	$ 4	3,277	16,598	(2,844)	(4,414)
Preferred Stock, Shares Outstanding, Ending Balance at Sep. 30, 2022		13,800
Common Shares Outstanding, beginning of period at Dec. 31, 2021			334,926
Shares Granted or Issued, Share-based Payment Arrangement [Abstract]
Treasury stock acquired	(17,000)		(17,390)
Issuance of shares under incentive and stock compensation plans and other			2,775
Return of shares under incentive and stock compensation plans to treasury stock			(793)
Common Shares Outstanding, at end of period at Sep. 30, 2022			319,518
Shares Granted or Issued, Share-based Payment Arrangement [Abstract]
Cash dividends declared per common share	$ 1.155
Cash dividends declared per preferred share	$ 1,125
Beginning balance at Jun. 30, 2022				3,264	16,388	(2,502)	(3,262)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under incentive and stock compensation plans and other				(8)
Stock-based compensation plans expense				21
Net income	$ 339				339
Dividends declared on preferred stock	(6)				(6)
Dividends declared on common stock					(123)
Treasury stock acquired						(350)
Issuance of shares under incentive and stock compensation plans from treasury stock and other								$ 9
Net shares acquired related to employee incentive and stock compensation plans						(1)
Total other comprehensive loss							(1,152)
Ending balance at Sep. 30, 2022	$ 12,955	$ 334	$ 4	$ 3,277	$ 16,598	$ (2,844)	$ (4,414)
Preferred Stock, Shares Outstanding, Ending Balance at Sep. 30, 2022		13,800
Common Shares Outstanding, beginning of period at Jun. 30, 2022			324,745
Shares Granted or Issued, Share-based Payment Arrangement [Abstract]
Treasury stock acquired			(5,353)
Issuance of shares under incentive and stock compensation plans and other			154
Return of shares under incentive and stock compensation plans to treasury stock			(28)
Common Shares Outstanding, at end of period at Sep. 30, 2022			319,518
Shares Granted or Issued, Share-based Payment Arrangement [Abstract]
Cash dividends declared per common share	$ 0.385
Cash dividends declared per preferred share	$ 375.00