Cash, Cash Equivalents and Investments (Tables)

3 Months Ended

Mar. 31, 2018

Cash and Cash Equivalents [Abstract]

Summary of Cash, Cash Equivalents and Investments

Our total cash, cash equivalents and investments are summarized below:

	March 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	$	330	$	—	$	—	$	330	$	336	$	—	$	—	$	336
Restricted cash, cash equivalents and investments
Insurance carriers security deposits	15		—		—		15		15		—		—		15
Payroll funds collected	523		—		—		523		1,095		—		—		1,095
Collateral for health benefits claims	71		—		—		71		69		—		—		69
Collateral for workers' compensation claims	87		1		—		88		98		1		—		99
Collateral to secure standby letter of credit	—		—		2		2		—		—		2		2
Total restricted cash, cash equivalents and investments	696		1		2		699		1,277		1		2		1,280
Restricted cash, cash equivalents and investments, noncurrent
Collateral for workers' compensation claims	159		23		—		182		125		37		—		162
Total	$	1,185	$	24	$	2	$	1,211	$	1,738	$	38	$	2	$	1,778

Amortized Cost, Gross Unrealized Gains and Losses, Fair Values and Related Maturities of Securities Available for Sale

The amortized cost, gross unrealized gains, gross unrealized losses, fair values, and related maturities of securities available for sale as of March 31, 2018 and December 31, 2017 are presented below:

(in millions)	Maturity (in years)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
March 31, 2018
U.S. treasuries	1-5 years	$	23	$	—	$	—	$	23
Exchange traded fund	N/A	1		—		—		1
Total		$	24	$	—	$	—	$	24
December 31, 2017
U.S. treasuries	1-5 years	$	37	$	—	$	—	$	37
Exchange traded fund	N/A	1		—		—		1
Total		$	38	$	—	$	—	$	38