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]
Net income	1,539				1,538	1
Other comprehensive income, net of tax	(42)			(42)
Issuances under employee stock purchase plan, Shares		1
Issuances under employee stock purchase plan	48		48
Issuance under equity incentive plans, Shares		5
Issuances under equity incentive plans	64		64
Stock-based compensation	224		224
Repurchases of common stock, shares		(14)
Repurchases of common stock	(1,121)		(36)		(1,085)
Dividends declared	(752)				(752)
Ending period (in shares) at Mar. 31, 2018		1,300
Ending Balance at Mar. 31, 2018	$ 20,651	$ 1	1,564	(170)	19,196	60
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	1,968				1,975	(7)
Other comprehensive income, net of tax	50			50
Issuances under employee stock purchase plan, Shares		1
Issuances under employee stock purchase plan	63		63
Issuance under equity incentive plans, Shares		4
Issuances under equity incentive plans	41		41
Stock-based compensation	144		144
Repurchases of common stock, shares		(13)
Repurchases of common stock	(903)		(36)		(867)
Dividends declared	$ (814)				(814)
Ending period (in shares) at Mar. 31, 2019	1,274	1,274
Ending Balance at Mar. 31, 2019	$ 22,091	$ 1	$ 2,494	$ 130	$ 19,326	$ 140