COMMON STOCK AND STOCKHOLDERS' (DEFICIT) EQUITY - SCHEDULE OF SHARE-BASED COMPENSATION (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	$ 110	$ 1,244	$ 494	$ 1,254
2021 ESPP
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	2	2	9	2
Time-Based RSUs
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	27	881	235	889
Market-Based RSUs
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	79	360	245	360
Options
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	2	1	5	3
Brokerage and transaction
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	2	6	4	6
Technology and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	25	503	166	505
Operations
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	0	16	5	16
Marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	0	41	3	41
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation	$ 83	$ 678	$ 316	$ 686