CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities
Net income	$ 63	$ 54
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	18	10
Stock-based compensation	9	9
Changes in operating assets and liabilities:
Accounts receivable	1	13
Unbilled revenue	(9)	11
Prepaid expenses	(12)	(11)
Other assets	(30)	(24)
Accounts payable and other current liabilities	9	(15)
Client deposits	(19)	(26)
Accrued wages	17	(15)
Accrued health insurance costs	0	(1)
Accrued workers' compensation costs	(2)	(3)
Payroll taxes payable and other payroll withholdings	(180)	(534)
Operating lease liabilities	(4)	0
Other liabilities	(3)	(4)
Net cash used in operating activities	(142)	(536)
Investing activities
Purchases of marketable securities	(30)	0
Proceeds from sale and maturity of marketable securities	31	14
Acquisitions of property and equipment	(12)	(12)
Net cash (used in) provided by investing activities	(11)	2
Financing activities
Repurchase of common stock	(38)	(8)
Proceeds from issuance of common stock	1	3
Awards effectively repurchased for required employee withholding taxes	(4)	(4)
Repayment of debt	(6)	(10)
Net cash used in financing activities	(47)	(19)
Net decrease in unrestricted and restricted cash and cash equivalents	(200)	(553)
Cash and cash equivalents, unrestricted and restricted:
Beginning of period	1,349	1,738
End of period	1,149	1,185
Supplemental disclosures of cash flow information
Interest paid	4	4
Income taxes paid, net	1	0
Supplemental schedule of noncash investing and financing activities
Payable for purchase of property and equipment	$ 5	$ 2