CASH, CASH EQUIVALENTS AND INVESTMENTS

Under the terms of the agreements with certain of our workers' compensation and health benefit insurance carriers, we are required to maintain collateral in trust accounts for the benefit of specified insurance carriers and to reimburse the carriers’ claim payments within our deductible layer. We invest a portion of the collateral amounts in marketable securities. We report the current and noncurrent portions of these trust accounts as restricted cash, cash equivalents and investments on the consolidated balance sheets.

We require our clients to prefund their payroll and related taxes and other withholding liabilities before payroll is processed or due for payment. This prefund is included in restricted cash, cash equivalents and investments as payroll funds collected, which is designated to pay pending payrolls, payroll tax liabilities and other payroll withholdings.

We also invest available corporate funds, primarily in fixed income securities which meet the requirements of our corporate investment policy and are classified as available for sale (AFS).

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