Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment
Beginning Balance (in shares) at Dec. 31, 2017			484
Beginning Balance at Dec. 31, 2017	$ 27,709	$ 912	$ 5	$ (1,837)	$ 21,389	$ (484)	$ (4)	$ 8,636	$ 916
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	10,073							10,073
Other comprehensive income (loss)	(547)					(547)
Exercise of common stock options (in shares)			7
Stock-based compensation and issuance of employee benefit plan stock	5,402				5,402
Ending Balance (in shares) at Dec. 31, 2018			491
Ending Balance at Dec. 31, 2018	43,549	$ 7	$ 5	(1,837)	26,791	(1,035)		19,625	$ 7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	11,588							11,588
Other comprehensive income (loss)	49					49
Exercise of common stock options (in shares)			7
Stock-based compensation and issuance of employee benefit plan stock	6,867				6,867
Ending Balance (in shares) at Dec. 31, 2019			498
Ending Balance at Dec. 31, 2019	62,060		$ 5	(1,837)	33,658	(986)		31,220
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	21,331							21,331
Other comprehensive income (loss)	806					806
Exercise of common stock options (in shares)			5
Stock-based compensation and issuance of employee benefit plan stock	9,207				9,207
Ending Balance (in shares) at Dec. 31, 2020			503
Ending Balance at Dec. 31, 2020	$ 93,404		$ 5	$ (1,837)	$ 42,865	$ (180)		$ 52,551