CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common stock	Additional paid-in capital	Treasury stock at cost	Retained earnings	Accumulated other comprehensive income (loss)
Stockholders' equity, beginning of period at Dec. 31, 2016		$ 2	$ 14,907	$ (19,205)	$ 14,946	$ (124)
Common stock, beginning of year (in shares) at Dec. 31, 2016		1,087
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued		$ 0
Common stock issued (in shares)		24
Common stock repurchased/forfeited		$ 0
Common stock repurchased/forfeited (in shares)		(82)
Common stock and stock-based awards issued			120
Tax withholdings related to net share settlements of restricted stock awards and units			(219)
Stock-based compensation			484
Other			1
Common stock repurchased				(2,687)
Net income (loss)	$ (1,017)				(1,017)
Dividends and dividend equivalents declared					0
Change in unrealized gains (losses) on investments	(66)					(66)
Change in unrealized gains (losses) on derivative instruments						(111)
Foreign currency translation adjustment						978
Tax benefit (provision) on above items						40
Common stock, end of period (in shares) at Dec. 31, 2017		1,029
Stockholders' equity, end of period at Dec. 31, 2017	$ 8,049	$ 2	15,293	(21,892)	13,929	717
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends and dividend equivalents declared per share or restricted stock unit (in usd per share)	$ 0
Common stock issued		$ 0
Common stock issued (in shares)		17
Common stock repurchased/forfeited		$ 0
Common stock repurchased/forfeited (in shares)		(131)
Common stock and stock-based awards issued			109
Tax withholdings related to net share settlements of restricted stock awards and units			(225)
Stock-based compensation			538
Other			1
Common stock repurchased				(4,502)
Net income (loss)	$ 2,530				2,530
Dividends and dividend equivalents declared					0
Change in unrealized gains (losses) on investments	$ (41)					(41)
Change in unrealized gains (losses) on derivative instruments						125
Foreign currency translation adjustment						(286)
Tax benefit (provision) on above items						(17)
Common stock, end of period (in shares) at Dec. 31, 2018	915	915
Stockholders' equity, end of period at Dec. 31, 2018	$ 6,281	$ 2	15,716	(26,394)	16,459	498
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends and dividend equivalents declared per share or restricted stock unit (in usd per share)	$ 0
Common stock issued		$ 0
Common stock issued (in shares)		15
Common stock repurchased/forfeited		$ 0
Common stock repurchased/forfeited (in shares)	(134)	(134)
Common stock and stock-based awards issued			104
Tax withholdings related to net share settlements of restricted stock awards and units			(202)
Stock-based compensation			505
Other			3
Common stock repurchased	$ (5,000)			(5,002)
Net income (loss)	1,786				1,786
Dividends and dividend equivalents declared					(491)
Change in unrealized gains (losses) on investments	$ 61					61
Change in unrealized gains (losses) on derivative instruments						(77)
Foreign currency translation adjustment						(99)
Tax benefit (provision) on above items						1
Common stock, end of period (in shares) at Dec. 31, 2019	796	796
Stockholders' equity, end of period at Dec. 31, 2019	$ 2,870	$ 2	$ 16,126	$ (31,396)	$ 17,754	$ 384
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends and dividend equivalents declared per share or restricted stock unit (in usd per share)	$ 0.56