Condensed Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent	Retained Earnings [Member]	Noncontrolling Interest [Member]
Beginning period (in shares) at Dec. 31, 2017		1,308
Beginning Balance at Dec. 31, 2017	$ 20,501	$ 1	$ 1,264	$ 165	$ 19,012	$ 59
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in noncontrolling interest	82					82
Net income (loss)	5,457				5,452	5
Other comprehensive income, net of tax	164			164
Issuances under employee stock purchase plan, Shares		1
Issuances under employee stock purchase plan	91		91
Issuance under equity incentive plans, Shares		12
Issuances under equity incentive plans	167		167
Stock-based compensation	667		667
Repurchases of common stock, shares		(27)
Repurchases of common stock	(2,067)		(71)		(1,996)
Dividends declared	(2,245)				(2,245)
Ending period (in shares) at Sep. 30, 2018		1,294
Ending Balance at Sep. 30, 2018	23,007	$ 1	2,118	36	20,706	146
Beginning period (in shares) at Jun. 30, 2018		1,296
Beginning Balance at Jun. 30, 2018	21,734	$ 1	1,844	2	19,825	62
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Change in noncontrolling interest	82					82
Net income (loss)	2,099				2,097	2
Other comprehensive income, net of tax	34			34
Issuances under employee stock purchase plan	43		43
Issuance under equity incentive plans, Shares		4
Issuances under equity incentive plans	58		58
Stock-based compensation	190		190
Repurchases of common stock, shares		(6)
Repurchases of common stock	(487)		(17)		(470)
Dividends declared	(746)				(746)
Ending period (in shares) at Sep. 30, 2018		1,294
Ending Balance at Sep. 30, 2018	$ 23,007	$ 1	2,118	36	20,706	146
Beginning period (in shares) at Dec. 31, 2018	1,282	1,282
Beginning Balance at Dec. 31, 2018	$ 21,534	$ 1	2,282	80	19,024	147
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	2,675				2,690	(15)
Other comprehensive income, net of tax	37			37
Issuances under employee stock purchase plan, Shares		2
Issuances under employee stock purchase plan	90		90
Issuance under equity incentive plans, Shares		8
Issuances under equity incentive plans	92		92
Stock-based compensation	479		479
Repurchases of common stock, shares		(26)
Repurchases of common stock	(1,748)		(73)		(1,675)
Dividends declared	$ (2,431)				(2,431)
Ending period (in shares) at Sep. 30, 2019	1,266	1,266
Ending Balance at Sep. 30, 2019	$ 20,736	$ 1	2,870	117	17,616	132
Beginning period (in shares) at Jun. 30, 2019		1,267
Beginning Balance at Jun. 30, 2019	22,751	$ 1	2,684	102	19,829	135
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(1,168)				(1,165)	(3)
Other comprehensive income, net of tax	15			15
Issuances under employee stock purchase plan, Shares		1
Issuances under employee stock purchase plan	27		27
Issuance under equity incentive plans, Shares		2
Issuances under equity incentive plans	10		10
Stock-based compensation	160		160
Repurchases of common stock, shares		(4)
Repurchases of common stock	(252)		(11)		(241)
Dividends declared	$ (807)				(807)
Ending period (in shares) at Sep. 30, 2019	1,266	1,266
Ending Balance at Sep. 30, 2019	$ 20,736	$ 1	$ 2,870	$ 117	$ 17,616	$ 132