RELATED PARTY TRANSACTIONS - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Oct. 31, 2021	Oct. 08, 2021	Jul. 31, 2021
2021 Convertible Notes | Amazon | Senior Notes
Related Party Transaction [Line Items]
Principal amount						$ 490,000,000
2021 Convertible Notes | Ford | Senior Notes
Related Party Transaction [Line Items]
Principal amount						415,000,000
2021 Convertible Notes | T Rowe Price | Senior Notes
Related Party Transaction [Line Items]
Principal amount						$ 400,000,000
Notes 2026 | Senior Notes
Related Party Transaction [Line Items]
Principal amount				$ 1,250,000,000
Notes 2026 | Senior Notes | T Rowe Price
Related Party Transaction [Line Items]
Principal amount					$ 285,000,000
Affiliated Entity | Ford
Related Party Transaction [Line Items]
Accrued liabilities	$ 16,000,000	$ 27,000,000
Affiliated Entity | Research And Development Services | Ford
Related Party Transaction [Line Items]
Expenses	71,000,000	66,000,000	$ 8,000,000
Affiliated Entity | Hosting Services | Amazon
Related Party Transaction [Line Items]
Expenses	$ 30,000,000	$ 6,000,000	$ 0