Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Number of shares of common stock [Member]	Common stock and additional paid-in capital [Member]	Accumulated deficit [Member]	Accumulated other comprehensive loss [Member]
Beginning Balance, Shares at Dec. 31, 2017		722.2
Balance as of beginning of period at Dec. 31, 2017	$ 25,241		$ 30,992	$ (5,072)	$ (679)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for basic and diluted EPS	2,311			2,311
Other comprehensive income (loss), net of taxes	(306)				(306)
Dividends declared on common stock	(877)			(877)
Issuance of common stock in connection with the Company’s equity award programs, Shares		0.6
Issuance of common stock in connection with the Company’s equity award programs	5		5
Stock-based compensation expense	61		61
Tax impact related to employee stock-based compensation expense	(57)		(57)
Repurchases of common stock, Shares		(56.4)
Repurchases of common stock	(10,787)			(10,787)
Ending Balance, Shares at Mar. 31, 2018		666.4
Balance as of end of period at Mar. 31, 2018	15,620		31,001	(14,387)	(994)
Beginning Balance, Shares at Dec. 31, 2017		722.2
Balance as of beginning of period at Dec. 31, 2017	25,241		30,992	(5,072)	(679)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for basic and diluted EPS	6,466
Ending Balance, Shares at Sep. 30, 2018		640.5
Balance as of end of period at Sep. 30, 2018	14,349		31,145	(15,987)	(809)
Beginning Balance, Shares at Mar. 31, 2018		666.4
Balance as of beginning of period at Mar. 31, 2018	15,620		31,001	(14,387)	(994)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for basic and diluted EPS	2,296			2,296
Other comprehensive income (loss), net of taxes	121				121
Issuance of common stock in connection with the Company’s equity award programs, Shares		0.8
Issuance of common stock in connection with the Company’s equity award programs	19		19
Stock-based compensation expense	93		93
Tax impact related to employee stock-based compensation expense	(65)		(65)
Repurchases of common stock, Shares		(18.2)
Repurchases of common stock	(3,190)			(3,190)
Other	15			15
Ending Balance, Shares at Jun. 30, 2018		649.0
Balance as of end of period at Jun. 30, 2018	14,909		31,048	(15,266)	(873)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for basic and diluted EPS	1,859			1,859
Other comprehensive income (loss), net of taxes	64				64
Dividends declared on common stock				(867)
Issuance of common stock in connection with the Company’s equity award programs, Shares		0.2
Issuance of common stock in connection with the Company’s equity award programs	13		13
Stock-based compensation expense	94		94
Tax impact related to employee stock-based compensation expense	(10)		(10)
Repurchases of common stock, Shares		(8.7)
Repurchases of common stock	(1,713)			(1,713)
Ending Balance, Shares at Sep. 30, 2018		640.5
Balance as of end of period at Sep. 30, 2018	$ 14,349		31,145	(15,987)	(809)
Beginning Balance, Shares at Dec. 31, 2018	629.6	629.6
Balance as of beginning of period at Dec. 31, 2018	$ 12,500		31,246	(17,977)	(769)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for basic and diluted EPS	1,992			1,992
Other comprehensive income (loss), net of taxes	253				253
Dividends declared on common stock	(879)			(879)
Issuance of common stock in connection with the Company’s equity award programs, Shares		0.7
Issuance of common stock in connection with the Company’s equity award programs	6		6
Stock-based compensation expense	64		64
Tax impact related to employee stock-based compensation expense	(73)		(73)
Repurchases of common stock, Shares		(15.9)
Repurchases of common stock	(3,031)			(3,031)
Ending Balance, Shares at Mar. 31, 2019		614.4
Balance as of end of period at Mar. 31, 2019	$ 10,832		31,243	(19,895)	(516)
Beginning Balance, Shares at Dec. 31, 2018	629.6	629.6
Balance as of beginning of period at Dec. 31, 2018	$ 12,500		31,246	(17,977)	(769)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for basic and diluted EPS	$ 6,139
Ending Balance, Shares at Sep. 30, 2019	596.2	596.2
Balance as of end of period at Sep. 30, 2019	$ 10,927		31,451	(20,136)	(388)
Beginning Balance, Shares at Mar. 31, 2019		614.4
Balance as of beginning of period at Mar. 31, 2019	10,832		31,243	(19,895)	(516)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for basic and diluted EPS	2,179			2,179
Other comprehensive income (loss), net of taxes	51				51
Issuance of common stock in connection with the Company’s equity award programs, Shares		0.8
Issuance of common stock in connection with the Company’s equity award programs	23		23
Stock-based compensation expense	97		97
Tax impact related to employee stock-based compensation expense	(50)		(50)
Repurchases of common stock, Shares		(13.1)
Repurchases of common stock	(2,349)			(2,349)
Other	11			11
Ending Balance, Shares at Jun. 30, 2019		602.1
Balance as of end of period at Jun. 30, 2019	10,794		31,313	(20,054)	(465)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for basic and diluted EPS	1,968			1,968
Other comprehensive income (loss), net of taxes	77				77
Dividends declared on common stock	(880)			(880)
Issuance of common stock in connection with the Company’s equity award programs, Shares		0.3
Issuance of common stock in connection with the Company’s equity award programs	37		37
Stock-based compensation expense	108		108
Tax impact related to employee stock-based compensation expense	(7)		(7)
Repurchases of common stock, Shares		(6.2)
Repurchases of common stock	$ (1,170)			(1,170)
Ending Balance, Shares at Sep. 30, 2019	596.2	596.2
Balance as of end of period at Sep. 30, 2019	$ 10,927		$ 31,451	$ (20,136)	$ (388)