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 (Loss) Income [Member]
Cumulative effect of new accounting principle in period of adoption				$ 320	$ (320)
Adjusted beginning balance	$ 26,503		$ 8,547	18,374	(421)
Balance at Dec. 31, 2017	26,503	$ 3	8,547	18,054	(101)
Balance (in shares) at Dec. 31, 2017		256.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,312			1,312
Other comprehensive income (loss)	(209)				(209)
Repurchase and retirement of common stock, value	(394)	$ 0	(56)	(338)
Repurchase and retirement of common stock, shares		(1.7)
Dividends and dividend equivalents	(198)			(198)
Issuance of common stock under employee stock plans, net of related tax benefits, Shares		1.1
Issuance of common stock under employee stock plans, net of related tax benefits	28		28
Convertible debenture repurchases and conversions	(30)		(30)
Adoption of ASU 2018-02 (Note 2)				91	(91)
Balance at Mar. 31, 2018	27,012	$ 3	8,489	19,241	(721)
Balance (in shares) at Mar. 31, 2018		255.5
Balance at Dec. 31, 2017	26,503	$ 3	8,547	18,054	(101)
Balance (in shares) at Dec. 31, 2017		256.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,366
Other comprehensive income (loss)	(270)
Repurchase and retirement of common stock, value	$ (795)
Repurchase and retirement of common stock, shares	(3.4)
Balance at Jun. 30, 2018	$ 28,725	$ 3	9,748	19,757	(783)
Balance (in shares) at Jun. 30, 2018		260.1
Balance at Mar. 31, 2018	27,012	$ 3	8,489	19,241	(721)
Balance (in shares) at Mar. 31, 2018		255.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,054			1,054
Other comprehensive income (loss)	(62)				(62)
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
Repurchase and retirement of common stock, value	(401)	$ 0	(60)	(341)
Repurchase and retirement of common stock, shares		(1.7)
Dividends and dividend equivalents	(197)			(197)
Issuance of common stock under employee stock plans, net of related tax benefits, Shares		0.3
Issuance of common stock under employee stock plans, net of related tax benefits	69		69
Balance at Jun. 30, 2018	28,725	$ 3	9,748	19,757	(783)
Balance (in shares) at Jun. 30, 2018		260.1
Cumulative effect of new accounting principle in period of adoption	26			26
Adjusted beginning balance	28,567		9,536	20,014	(986)
Balance at Dec. 31, 2018	28,541	$ 3	9,536	19,988	(986)
Balance (in shares) at Dec. 31, 2018		257.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,551			1,551
Other comprehensive income (loss)	363				363
Repurchase and retirement of common stock, value	(294)	$ 0	(71)	(223)
Repurchase and retirement of common stock, shares		(1.1)
Dividends and dividend equivalents	(206)			(206)
Issuance of common stock under employee stock plans, net of related tax benefits, Shares		1.1
Issuance of common stock under employee stock plans, net of related tax benefits	69		69
Convertible debenture repurchases and conversions	(52)		(52)
Balance at Mar. 31, 2019	29,998	$ 3	9,482	21,136	(623)
Balance (in shares) at Mar. 31, 2019		257.4
Balance at Dec. 31, 2018	28,541	$ 3	9,536	19,988	(986)
Balance (in shares) at Dec. 31, 2018		257.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,690
Other comprehensive income (loss)	603
Repurchase and retirement of common stock, value	$ (752)
Repurchase and retirement of common stock, shares	(2.8)
Balance at Jun. 30, 2019	$ 30,793	$ 3	9,494	21,679	(383)
Balance (in shares) at Jun. 30, 2019		255.9
Balance at Mar. 31, 2019	29,998	$ 3	9,482	21,136	(623)
Balance (in shares) at Mar. 31, 2019		257.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,139			1,139
Other comprehensive income (loss)	240				240
Repurchase and retirement of common stock, value	(458)	$ 0	(70)	(388)
Repurchase and retirement of common stock, shares		(1.7)
Dividends and dividend equivalents	(208)			(208)
Issuance of common stock under employee stock plans, net of related tax benefits, Shares		0.2
Issuance of common stock under employee stock plans, net of related tax benefits	91		91
Convertible debenture repurchases and conversions	(9)		(9)
Balance at Jun. 30, 2019	$ 30,793	$ 3	$ 9,494	$ 21,679	$ (383)
Balance (in shares) at Jun. 30, 2019		255.9