Equity Incentive Plans - Additional Information (Detail) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended			6 Months Ended
	Mar. 31, 2018 USD ($) Tranches Milestone shares	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) $ / shares	Jun. 30, 2020 USD ($)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation					$ 1,088	$ 558
2018 CEO Performance Award [Member] | Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of stock options grant | shares	101,300,000
Number of vesting tranches CEO Performance Award consists | Tranches	12
Increase to market capitalization for each remaining milestone	$ 50,000
Number of operational milestones focused on total revenue | Milestone	8
Number of operational milestones focused on adjusted EBITDA | Milestone	8
Award vesting description					The 2018 CEO Performance Award consists of 12 vesting tranches with a vesting schedule based entirely on the attainment of both operational milestones (performance conditions) and market conditions, assuming continued employment either as the CEO or as both Executive Chairman and Chief Product Officer and service through each vesting date. Each of the 12 vesting tranches of the 2018 CEO Performance Award will vest upon certification by the Board of Directors that both (i) the market capitalization milestone for such tranche, which begins at $100.0 billion for the first tranche and increases by increments of $50.0 billion thereafter (based on both a six calendar month trailing average and a 30 calendar day trailing average, counting only trading days), has been achieved, and (ii) any one of the following eight operational milestones focused on total revenue or any one of the eight operational milestones focused on Adjusted EBITDA have been achieved for the four consecutive fiscal quarters on an annualized basis and subsequently reported by us in our consolidated financial statements filed with our Forms 10-Q and/or 10-K.
Holding period of shares post-exercise	5 years
Payment of exercise price per share | $ / shares					$ 70.01
Stock-based compensation		$ 176		$ 167	$ 475	$ 233
2018 CEO Performance Award [Member] | Chief Executive Officer [Member] | Operational Milestones Probable of Being Achieved [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Operational milestones based on total revenue			$ 55,000
Operational milestones based on annualized adjusted EBITDA		10,000
Recognized catch-up expense during period		124	$ 116
Unrecognized compensation expense		105			$ 105
Weighted-average period of recognition of unrecognized compensation, in years					8 months 12 days
2018 CEO Performance Award [Member] | Chief Executive Officer [Member] | Operational Milestones Not Considered Probable Achievement [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense		$ 396			$ 396
2018 CEO Performance Award [Member] | Chief Executive Officer [Member] | First Tranche Milestone [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Market capitalization	$ 100,000