
	December 31,
	2022		2021
Cash and cash equivalents:
Cash	$	6,176	$	7,308
Money market funds	8,305		8,850
U.S. government securities	—		25
U.S. government agency securities	16		108
Certificates of deposit and time deposits	156		250
Corporate debt securities	28		60
Total cash and cash equivalents	14,681		16,601
Marketable securities:
Marketable debt securities:
U.S. government securities	8,708		10,901
U.S. government agency securities	4,989		5,927
Corporate debt securities	12,335		14,569
Total marketable debt securities	26,032		31,397
Marketable equity securities	25		—
Total marketable securities	26,057		31,397
Restricted cash:
Restricted cash included in prepaid expenses and other current assets	294		149
Restricted cash included in other assets	621		115
Total restricted cash	915		264
Total cash, cash equivalents, marketable securities, and restricted cash	$	41,653	$	48,262

The following table summarizes our available-for-sale marketable debt securities and cash equivalents with unrealized losses as of December 31, 2022 and 2021, aggregated by major security type and the length of time that individual securities have been in a continuous loss position (in millions):


	December 31, 2022
	Less than 12 months				12 months or greater				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. government securities	$	5,008	$	(234)	$	3,499	$	(247)	$	8,507	$	(481)
U.S. government agency securities	524		(17)		4,415		(308)		4,939		(325)
Corporate debt securities	4,555		(249)		7,256		(634)		11,811		(883)
Total	$	10,087	$	(500)	$	15,170	$	(1,189)	$	25,257	$	(1,689)


	December 31, 2021
	Less than 12 months				12 months or greater				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. government securities	$	5,184	$	(38)	$	30	$	—	$	5,214	$	(38)
U.S. government agency securities	5,029		(61)		2		—		5,031		(61)
Corporate debt securities	10,041		(93)		40		(1)		10,081		(94)
Total	$	20,254	$	(192)	$	72	$	(1)	$	20,326	$	(193)

The increase in the gross unrealized losses for the year ended December 31, 2022 is due to higher interest rates. The allowance for credit losses and the gross unrealized gains on our marketable debt securities was not material as of December 31, 2022 and 2021.