Stockholders' Equity - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Feb. 29, 2016
Class of Stock [Line Items]
Preferred stock, authorized (in shares)	500,000,000	500,000,000
Preferred stock, par value (in usd per share)	$ 0.01	$ 0.01
Preferred stock, outstanding (in shares)	0	0
Common shares outstanding plus underlying outstanding stock awards	518,000,000	512,000,000	507,000,000
Repurchases of common stock	$ 0	$ 0	$ 0
Net unrecognized compensation cost related to unvested stock-based compensation arrangements	$ 13,300,000,000
Compensation cost expected to be expensed in next twelve months, percentage	50.00%
Net unrecognized compensation cost related to unvested stock-based compensation arrangements, weighted average recognition period (in years)	1 year 2 months 12 days
Estimated forfeiture rate	27.00%
Common stock available for future issuance to employees (in shares)	102,000,000
Restricted Stock Units
Class of Stock [Line Items]
Fair value of units vested	$ 15,500,000,000	$ 11,700,000,000	$ 11,400,000,000
Minimum
Class of Stock [Line Items]
Award vesting period	2 years
Maximum
Class of Stock [Line Items]
Award vesting period	5 years
February 2016 Program
Class of Stock [Line Items]
Stock repurchase, authorized amount				$ 5,000,000,000.0