Our total cash, cash equivalents and investments are summarized in the table below:



	December 31, 2018								December 31, 2017
(in millions)	Cash and cash equivalents		Available-for-sale marketable securities		Certificate of deposits		Total		Cash and cash equivalents		Available-for-sale marketable securities		Certificate of deposits		Total
Cash and cash equivalents	$	228	$	—	$	—	$	228	$	336	$	—	$	—	$	336
Investments	—		54		—		54		—		—		—		—
Restricted cash, cash equivalents and investments
Insurance carriers security deposits	15		—		—		15		15		—		—		15
Payroll funds collected	783		—		—		783		1,095		—		—		1,095
Collateral for health benefits claims	75		—		—		75		69		—		—		69
Collateral for workers' compensation claims	66		1		—		67		98		1		—		99
Collateral to secure standby letter of credit	—		—		2		2		—		—		2		2
Total restricted cash, cash equivalents and investments, current	939		1		2		942		1,277		1		2		1,280
Investments, noncurrent	—		135		—		135		—		—		—		—
Restricted cash, cash equivalents and investments, noncurrent
Collateral for workers' compensation claims	182		5		—		187		125		37		—		162
Total	$	1,349	$	195	$	2	$	1,546	$	1,738	$	38	$	2	$	1,778