FAIR VALUE DISCLOSURES - Unobservable Input Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Interest rate lock commitments
Servicing Liability at Fair Value, Amount [Roll Forward]
Beginning balance	$ 0	$ 0	$ 0
Issuances			0
Settlement of 2019 Convertible Notes	(5)	0
Exercise of warrants		0	0
Net change in fair value		0	0
Additions	5
Ending balance	0	0	0
Warrants
Servicing Liability at Fair Value, Amount [Roll Forward]
Beginning balance	0	5	18
Issuances			1
Settlement of 2019 Convertible Notes	0	0
Exercise of warrants		(7)	(7)
Net change in fair value		2	(7)
Additions	0
Ending balance	0	0	5
Embedded Conversion Option
Servicing Liability at Fair Value, Amount [Roll Forward]
Beginning balance	0	42	0
Issuances			42
Settlement of 2019 Convertible Notes	0	(65)
Exercise of warrants		0	0
Net change in fair value		23	0
Additions	0
Ending balance	$ 0	$ 0	$ 42