CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) income	$ (1,353,000,000)	$ (662,000,000)	$ (253,000,000)
Adjustments to reconcile net loss to cash, cash equivalents, and restricted cash (used in) provided by operating activities:
Depreciation and amortization	83,000,000	47,000,000	39,000,000
Amortization of right of use asset	7,000,000	8,000,000	24,000,000
Stock-based compensation	171,000,000	536,000,000	38,000,000
Warrant fair value adjustment	0	(12,000,000)	(31,000,000)
Gain on settlement of lease liabilities	0	(5,000,000)	0
Inventory valuation adjustment	737,000,000	56,000,000	8,000,000
Changes in fair value of derivative instruments	0	0	23,000,000
Goodwill impairment	60,000,000	0	0
Changes in fair value of equity securities	35,000,000	(35,000,000)	0
Payment-in-kind interest	0	0	4,000,000
Net fair value adjustments and loss on sale of mortgage loans held for sale	(1,000,000)	(4,000,000)	(3,000,000)
Origination of mortgage loans held for sale	(118,000,000)	(196,000,000)	(128,000,000)
Proceeds from sale and principal collections of mortgage loans held for sale	128,000,000	197,000,000	126,000,000
Loss on early extinguishment of debt	25,000,000	0	0
Changes in operating assets and liabilities:
Escrow receivable	54,000,000	(83,000,000)	12,000,000
Real estate inventory	896,000,000	(5,656,000,000)	834,000,000
Other assets	37,000,000	(52,000,000)	3,000,000
Accounts payable and other accrued liabilities	(25,000,000)	76,000,000	(4,000,000)
Interest payable	2,000,000	4,000,000	(3,000,000)
Lease liabilities	(8,000,000)	(13,000,000)	(7,000,000)
Net cash provided by (used in) operating activities	730,000,000	(5,794,000,000)	682,000,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(37,000,000)	(33,000,000)	(17,000,000)
Purchase of intangible assets	0	(1,000,000)	0
Purchase of marketable securities	(28,000,000)	(486,000,000)	(175,000,000)
Proceeds from sales, maturities, redemptions and paydowns of marketable securities	328,000,000	92,000,000	170,000,000
Purchase of non-marketable equity securities	(25,000,000)	(15,000,000)	0
Proceeds from sale of non-marketable equity securities	3,000,000	0	0
Capital returns from non-marketable equity securities	3,000,000	0	0
Acquisitions, net of cash acquired	(10,000,000)	(33,000,000)	0
Net cash provided by (used in) investing activities	234,000,000	(476,000,000)	(22,000,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of convertible senior notes, net of issuance costs	0	953,000,000	0
Purchase of capped calls related to the convertible senior notes	0	(119,000,000)	0
Proceeds from exercise of stock options	4,000,000	15,000,000	8,000,000
Proceeds from issuance of common stock for ESPP	2,000,000	0	0
Proceeds from warrant exercise	0	22,000,000	0
Proceeds from Business Combination and PIPE offering	0	0	1,014,000,000
Proceeds from the February 2021 Offering	0	886,000,000	0
Proceeds from non-recourse asset-backed debt	10,108,000,000	11,499,000,000	1,309,000,000
Principal payments on non-recourse asset-backed debt	(11,822,000,000)	(5,838,000,000)	(2,130,000,000)
Proceeds from other secured borrowings	114,000,000	192,000,000	125,000,000
Principal payments on other secured borrowings	(121,000,000)	(192,000,000)	(121,000,000)
Payment of loan origination fees and debt issuance costs	(26,000,000)	(47,000,000)	(3,000,000)
Payment for early extinguishment of debt	(10,000,000)	0	0
Net cash (used in) provided by financing activities	(1,751,000,000)	7,342,000,000	161,000,000
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	(787,000,000)	1,072,000,000	821,000,000
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH – Beginning of year	2,578,000,000	1,506,000,000	685,000,000
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH – End of year	1,791,000,000	2,578,000,000	1,506,000,000
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION – Cash paid during the period for interest	355,000,000	122,000,000	57,000,000
DISCLOSURES OF NONCASH FINANCING ACTIVITIES:
Stock-based compensation expense capitalized for internally developed software	16,000,000	12,000,000	0
Conversion of preferred stock to common stock	0	0	1,386,000,000
Issuance of issuer stock rights in extinguishment of the 2019 Convertible Notes	0	0	213,000,000
Recognition of warrant liability	0	0	81,000,000
Issuance of common stock in extinguishment of warrant liabilities	0	(35,000,000)	0
RECONCILIATION TO CONSOLIDATED BALANCE SHEETS:
Cash and cash equivalents	1,137,000,000	1,731,000,000	1,413,000,000
Restricted cash	654,000,000	847,000,000	93,000,000
Cash, cash equivalents, and restricted cash	1,791,000,000	2,578,000,000	1,506,000,000
Series E Convertible Preferred Stock
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of Series E preferred stock	0	0	2,000,000
Common Stock
CASH FLOWS FROM FINANCING ACTIVITIES:
Issuance cost of common stock	$ 0	$ (29,000,000)	$ (43,000,000)