Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Cumulative effect of changes in accounting principles, net of tax	Number of shares of common stock [Member]	Common stock and additional paid-in capital [Member]	Accumulated deficit [Member]	Accumulated deficit [Member] Cumulative effect of changes in accounting principles, net of tax	Accumulated other comprehensive loss [Member]
Beginning Balance, Shares at Dec. 31, 2018			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
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
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
Balance as of end of period at Sep. 30, 2019	$ 10,927			31,451	(20,136)		(388)
Beginning Balance, Shares at Dec. 31, 2019	591.4		591.4
Balance as of beginning of period at Dec. 31, 2019	$ 9,673	$ (2)		31,531	(21,330)	$ (2)	(528)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for basic and diluted EPS	1,825				1,825
Other comprehensive income (loss), net of taxes	(134)						(134)
Dividends declared on common stock	(938)				(938)
Issuance of common stock in connection with the Company’s equity award programs, Shares			0.9
Issuance of common stock in connection with the Company’s equity award programs	10			10
Stock-based compensation expense	52			52
Tax impact related to employee stock-based compensation expense	(68)			(68)
Repurchases of common stock, Shares			(4.3)
Repurchases of common stock	(933)				(933)
Ending Balance, Shares at Mar. 31, 2020			588.0
Balance as of end of period at Mar. 31, 2020	$ 9,485			31,525	(21,378)		(662)
Beginning Balance, Shares at Dec. 31, 2019	591.4		591.4
Balance as of beginning of period at Dec. 31, 2019	$ 9,673	$ (2)		31,531	(21,330)	$ (2)	(528)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for basic and diluted EPS	$ 5,649
Ending Balance, Shares at Sep. 30, 2020	583.5		583.5
Balance as of end of period at Sep. 30, 2020	$ 10,959			31,713	(19,851)		(903)
Beginning Balance, Shares at Mar. 31, 2020			588.0
Balance as of beginning of period at Mar. 31, 2020	9,485			31,525	(21,378)		(662)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for basic and diluted EPS	1,803				1,803
Other comprehensive income (loss), net of taxes	(121)						(121)
Issuance of common stock in connection with the Company’s equity award programs, Shares			1.0
Issuance of common stock in connection with the Company’s equity award programs	65			65
Stock-based compensation expense	101			101
Tax impact related to employee stock-based compensation expense	(81)			(81)
Repurchases of common stock, Shares			(2.6)
Repurchases of common stock	(591)				(591)
Other	(2)				(2)
Ending Balance, Shares at Jun. 30, 2020			586.4
Balance as of end of period at Jun. 30, 2020	10,659			31,610	(20,168)		(783)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income for basic and diluted EPS	2,021				2,021
Other comprehensive income (loss), net of taxes	(120)						(120)
Dividends declared on common stock	(952)				(952)
Issuance of common stock in connection with the Company’s equity award programs, Shares			0.1
Issuance of common stock in connection with the Company’s equity award programs	5			5
Stock-based compensation expense	109			109
Tax impact related to employee stock-based compensation expense	(11)			(11)
Repurchases of common stock, Shares			(3.0)
Repurchases of common stock	$ (752)				(752)
Ending Balance, Shares at Sep. 30, 2020	583.5		583.5
Balance as of end of period at Sep. 30, 2020	$ 10,959			$ 31,713	$ (19,851)		$ (903)