INVESTMENTS (Tables)

12 Months Ended

Dec. 31, 2023

Investments, Debt and Equity Securities [Abstract]

Schedule of Financial Instruments by Significant Categories and Fair Value Measurement on a Recurring Basis

The following tables summarize our financial instruments by significant categories and fair value measurement on a recurring basis as of December 31, 2023 and December 31, 2022 and the amortized cost, gross unrealized gains, gross unrealized losses, and fair value of our AFS investments:

(in millions)	Fair Value Level	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Cash and Cash Equivalents		Investments		Restricted Cash, Cash Equivalents and Investments
December 31, 2023
Cash equivalents:
Money market mutual funds	Level 1	$	183	$	—	$	—	$	183	$	96	$	—	$	87
U.S. treasuries	Level 2	7		—		—		7		5		—		2
Total cash equivalents		190		—		—		190		101		—		89
AFS Investments:
Asset-backed securities	Level 2	41		—		(1)		40		—		40		—
Corporate bonds	Level 2	135		1		—		136		—		103		33
Agency securities	Level 2	40		—		(1)		39		—		10		29
U.S. treasuries	Level 2	231		1		(1)		231		—		47		184
Certificate of deposit	Level 2	2		—		—		2		—		—		2
Other debt securities	Level 2	8		—		—		8		—		8		—
Total AFS Investments		$	457	$	2	$	(3)	$	456	$	—	$	208	$	248

(in millions)	Fair Value Level	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Cash and Cash Equivalents		Investments		Restricted Cash, Cash Equivalents and Investments
December 31, 2022
Cash equivalents:
Money market mutual funds	Level 1	$	314	$	—	$	—	$	314	$	225	$	—	$	89
U.S. treasuries	Level 2	18		—		—		18		18		—		—
Total cash equivalents		332		—		—		332		243		—		89
AFS Investments:
Asset-backed securities	Level 2	42		—		(2)		40		—		40		—
Corporate bonds	Level 2	140		—		(1)		139		—		112		27
Agency securities	Level 2	33		—		(1)		32		—		5		27
U.S. treasuries	Level 2	229		—		—		229		—		62		167
Certificate of deposit	Level 2	12		—		—		12		—		—		12
Other debt securities	Level 2	8		—		—		8		—		7		1
Total AFS Investments		$	464	$	—	$	(4)	$	460	$	—	$	226	$	234

Schedule of Fair Value of Debt Investments by Contractual Maturity

The fair value of debt investments by contractual maturity are shown below:

(in millions)	December 31, 2023
One year or less	$	93
Over one year through five years	332
Over five years through ten years	11
Over ten years	20
Total fair value	$	456

Schedule of Proceeds from Available-for-sale Securities

The gross proceeds from sales and maturities of AFS securities for the years ended December 31, 2023, 2022, and 2021 are presented below. We had immaterial gross realized gains and losses from sales of investments for the year ended December 31, 2021.

	Year Ended December 31,
(in millions)	2023		2022		2021
Gross realized losses	$	(1)	$	(18)	$	—
Gross proceeds from sales	150		227		162
Gross proceeds from maturities	137		253		187
Total	$	286	$	462	$	349