Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance, beginning (in shares) at Dec. 31, 2016		263.7
Balance, beginning at Dec. 31, 2016	$ 25,101	$ 3	$ 8,805	$ 16,560	$ (267)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,843			3,843
Other comprehensive income (loss)	166				166
Premiums for and settlement of equity options	1		1
Repurchase and retirement of common stock, shares		(10.5)
Repurchase and retirement of common stock	(1,998)		(356)	(1,642)
Dividends and dividend equivalents	(707)			(707)
Issuance of common stock under employee stock plans, net of related tax benefits (in shares)		2.9
Issuance of common stock under employee stock plans, net of related tax benefits	342		342
Convertible debenture conversions	(245)		(245)
Balance, ending (in shares) at Dec. 31, 2017		256.1
Balance, ending at Dec. 31, 2017	26,503	$ 3	8,547	18,054	(101)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	26,503		8,547	18,374	(421)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting principle in period of adoption				320	(320)
Net income	3,750			3,750
Other comprehensive income (loss)	(474)				(474)
Issuance of common stock under Equity Units stock purchase contracts, shares		6.0
Issuance of common stock under Equity Units stock purchase contracts	1,250		1,250
Premiums for and settlement of equity options	$ 1		1
Repurchase and retirement of common stock, shares	(6.8)	(6.8)
Repurchase and retirement of common stock	$ (1,685)		(243)	(1,442)
Dividends and dividend equivalents	(785)			(785)
Issuance of common stock under employee stock plans, net of related tax benefits (in shares)		2.1
Issuance of common stock under employee stock plans, net of related tax benefits	318		318
Convertible debenture conversions	(337)		(337)
Reclassification of stranded tax effects resulting from the Tax Cuts and Jobs Act	91			91	(91)
Balance, ending (in shares) at Dec. 31, 2018		257.4
Balance, ending at Dec. 31, 2018	28,541	$ 3	9,536	19,988	(986)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance	28,567		9,536	20,014	(986)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting principle in period of adoption	26			26
Net income	4,807
Other comprehensive income (loss)	$ 690				690
Repurchase and retirement of common stock, shares	(6.3)	(6.3)
Repurchase and retirement of common stock	$ (1,701)		(275)	(1,426)
Dividends and dividend equivalents	(822)			(822)
Issuance of common stock under employee stock plans, net of related tax benefits (in shares)		1.8
Issuance of common stock under employee stock plans, net of related tax benefits	396		396
Convertible debenture conversions	(209)		(209)
Balance, ending (in shares) at Dec. 31, 2019		252.9
Balance, ending at Dec. 31, 2019	$ 31,728	$ 3	$ 9,448	$ 22,573	$ (296)