CONTINGENTLY REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ (DEFICIT) EQUITY (Tables)

12 Months Ended

Dec. 31, 2021

Temporary Equity And Stockholders' Equity Disclosure [Abstract]

Temporary Equity

Contingently redeemable convertible preferred stock consisted of the following shares as of December 31, 2020 (in millions)):

Contingently Redeemable Convertible Preferred Stock	Shares Authorized	Shares Outstanding	Carrying and Liquidation Value
Series A	118	118	$	600
Series B	66	66	500
Series C	42	39	350
Series D	121	121	1,297
Series E	161	161	2,497
Total	508	504	$	5,244

Share-based Payment Arrangement, Activity

The following table summarizes the Company’s stock option and restricted stock unit activity during the year ended December 31, 2021:

	Stock Options						RSUs
				Weighted
				Average				Weighted
	Number of	Weighted		Remaining	Aggregate		Number of	Average
	Shares	Average		Contractual	Intrinsic Value		Shares	Grant Date
	(in millions)	Exercise Price		Life (years)	(in millions)		(in millions)	Fair Value
Outstanding at December 31, 2020	39	$	4.19				12	$	7.24
Granted	29	22.06					26	43.94
Exercised / Vested	(1)	3.29					—	—
Forfeited / Cancelled	(2)	4.73					(1)	27.36
Outstanding at December 31, 2021	65	$	12.06	7.7	$	6,018	37	$	31.24
Vested and expected to vest at December 31, 2021	65	$	12.06	7.7	$	6,018	37	$	31.24
Exercisable at December 31, 2021	22	$	3.95	6.6	$	2,161	—	$	—

The following table summarizes the changes in the Company’s outstanding warrants to purchase common stock:

				Weighted
		Weighted		Average
		Average		Remaining
	Shares	Exercise		Contractual
Common Stock Warrants	(in millions)	Price		Term
Outstanding at December 31, 2020	8	$	6.00	7.6
Granted	—	—
Transferred from preferred stock warrant	4	9.09
Exercised	—	—
Cancelled, forfeited or expired	—	5.66
Outstanding at December 31, 2021	12	$	6.84	7.0
Exercisable at December 31, 2021	12	$	6.84	7.0

The following table summarizes the changes in the Company’s outstanding warrants to purchase preferred stock:

		Weighted
		Average
	Shares	Exercise
Preferred Stock Warrants	(in millions)	Price
Outstanding at December 31, 2020	4	$	9.09
Granted	—	—
Exercised	—	—
Cancelled, forfeited, expired, or converted	(4)	(9.09)
Outstanding at December 31, 2021	—	$	—
Exercisable at December 31, 2021	—	$	—

Schedule Of Share-Based Payment Award, Equity Instruments Other Than Options, Valuation Assumptions

The weighted-average assumptions used in the Black-Scholes model for warrants granted during the years ended December 31, 2019 and 2020 are as follows:

	Years Ended December 31,
	2019		2020
Volatility	44.4	%	54.7	%
Dividend yield	—	%	—	%
Risk-free rate	1.9	%	0.7	%
Contractual term (in years)	10.0		10.0