Stock Compensation - Effect on Shares Outstanding and Treasury Shares (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change In Treasury Stock Roll Forward [Roll Forward]
Treasury stock (in shares)	821,461,787	808,784,381	795,665,646	757,657,217
Repurchases (in shares)	23,430,215	27,398,701	49,482,220
Total issued (in shares)	(10,751,252)	(14,208,395)	(11,468,610)
Director
Change In Treasury Stock Roll Forward [Roll Forward]
Director deferred stock units issued (in shares)	(1,557)	(71,571)	(5,181)
Employee Stock Option
Change In Treasury Stock Roll Forward [Roll Forward]
Exercised (in shares)	(8,392,354)	(11,529,174)	(8,432,458)
Stock applied to taxes (in shares)	0	0	0
Total issued (in shares)	(9,137,837)	(12,327,980)	(9,252,336)
Employee Stock Option | Director
Change In Treasury Stock Roll Forward [Roll Forward]
Director deferred stock units issued (in shares)	0	0	0
Restricted Stock Units (RSUs)
Change In Treasury Stock Roll Forward [Roll Forward]
Vested RSUs (in shares)	(2,034,933)	(2,370,762)	(2,769,994)
Stock applied to taxes (in shares)	421,518	490,347	553,720
Total issued (in shares)	(1,613,415)	(1,880,415)	(2,216,274)
Restricted Stock Units (RSUs) | Director
Change In Treasury Stock Roll Forward [Roll Forward]
Director deferred stock units issued (in shares)	0	0	0
Employee stock purchase plan
Change In Treasury Stock Roll Forward [Roll Forward]
Exercised (in shares)	(745,483)
Employee stock purchase plan | Employee Stock Option
Change In Treasury Stock Roll Forward [Roll Forward]
Exercised (in shares)	(745,483)	(798,806)	(819,878)
Employee stock purchase plan | Restricted Stock Units (RSUs)
Change In Treasury Stock Roll Forward [Roll Forward]
Vested RSUs (in shares)	0	0	0