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				(71)
Stock-based compensation plans expense				79
Net income	$ 1,154				1,154
Dividends declared on preferred stock	(10)				(10)
Dividends declared on common stock					(249)
Treasury stock acquired	(691)					(691)
Issuance of shares under incentive and stock compensation plans from treasury stock and other								$ 102
Net shares acquired related to employee incentive and stock compensation plans						(26)
Total other comprehensive income (loss)							(600)
Ending balance at Jun. 30, 2021	$ 18,244	$ 334	$ 4	4,330	14,813	(1,807)	570
13800000 at Jun. 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	(11,000)		(11,036)
Issuance of shares under incentive and stock compensation plans and other			2,057
Return of shares under incentive and stock compensation plans to treasury stock			(512)
Common Shares Outstanding, at end of period at Jun. 30, 2021			348,998
Shares Granted or Issued, Share-based Payment Arrangement [Abstract]
Cash dividends declared per common share	$ 0.700
Cash dividends declared per preferred share	$ 750.00
Beginning balance at Mar. 31, 2021				4,310	14,036	(1,246)	264
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under incentive and stock compensation plans and other				(2)
Stock-based compensation plans expense				22
Net income	$ 905				905
Dividends declared on preferred stock	(5)				(5)
Dividends declared on common stock					(123)
Treasury stock acquired						(568)
Issuance of shares under incentive and stock compensation plans from treasury stock and other								8
Net shares acquired related to employee incentive and stock compensation plans						(1)
Total other comprehensive income (loss)							306
Ending balance at Jun. 30, 2021	$ 18,244	$ 334	$ 4	4,330	14,813	(1,807)	570
13800000 at Jun. 30, 2021		13,800
Common Shares Outstanding, beginning of period at Mar. 31, 2021			357,517
Shares Granted or Issued, Share-based Payment Arrangement [Abstract]
Treasury stock acquired			(8,650)
Issuance of shares under incentive and stock compensation plans and other			143
Return of shares under incentive and stock compensation plans to treasury stock			(12)
Common Shares Outstanding, at end of period at Jun. 30, 2021			348,998
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				(122)
Stock-based compensation plans expense				77
Net income	887				887
Dividends declared on preferred stock	(10)				(10)
Dividends declared on common stock					(253)
Treasury stock acquired	(850)					(850)
Issuance of shares under incentive and stock compensation plans from treasury stock and other								142
Net shares acquired related to employee incentive and stock compensation plans						(54)
Total other comprehensive income (loss)							(3,434)
Ending balance at Jun. 30, 2022	$ 14,226	$ 334	$ 4	3,264	16,388	(2,502)	(3,262)
13800000 at Jun. 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	(12,000)		(12,037)
Issuance of shares under incentive and stock compensation plans and other			2,621
Return of shares under incentive and stock compensation plans to treasury stock			(765)
Common Shares Outstanding, at end of period at Jun. 30, 2022			324,745
Shares Granted or Issued, Share-based Payment Arrangement [Abstract]
Cash dividends declared per common share	$ 0.770
Cash dividends declared per preferred share	$ 750.00
Beginning balance at Mar. 31, 2022				3,249	16,077	(2,068)	(1,699)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under incentive and stock compensation plans and other				(7)
Stock-based compensation plans expense				22
Net income	$ 442				442
Dividends declared on preferred stock	(5)				(5)
Dividends declared on common stock					(126)
Treasury stock acquired						(450)
Issuance of shares under incentive and stock compensation plans from treasury stock and other								$ 18
Net shares acquired related to employee incentive and stock compensation plans						(2)
Total other comprehensive income (loss)							(1,563)
Ending balance at Jun. 30, 2022	$ 14,226	$ 334	$ 4	$ 3,264	$ 16,388	$ (2,502)	$ (3,262)
13800000 at Jun. 30, 2022		13,800
Common Shares Outstanding, beginning of period at Mar. 31, 2022			330,709
Shares Granted or Issued, Share-based Payment Arrangement [Abstract]
Treasury stock acquired			(6,355)
Issuance of shares under incentive and stock compensation plans and other			411
Return of shares under incentive and stock compensation plans to treasury stock			(20)
Common Shares Outstanding, at end of period at Jun. 30, 2022			324,745
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