CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating activities
Net income	$ 131	$ 146
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	30	21
Amortization of ROU asset, lease modification, impairment, and abandonment	2	3
Stock based compensation	11	12
Deferred income taxes	0	2
Provision for doubtful accounts	1	0
Other	0	2
Changes in operating assets and liabilities:
Accounts receivable, net	3	8
Unbilled revenue, net	5	7
Other assets and prepaid expenses, net	(24)	5
Other payroll assets	(180)	(16)
Accounts payable and other liabilities	30	10
Client deposits and other client liabilities	25	28
Accrued wages	(21)	188
Accrued health insurance costs, net	(5)	(8)
Accrued workers' compensation costs, net	(1)	1
Payroll taxes payable and other payroll withholdings	(80)	(191)
Operating lease liabilities	(4)	(4)
Net cash provided by (used in) operating activities	(77)	214
Investing activities
Purchases of marketable securities	(82)	(91)
Proceeds from sale and maturity of marketable securities	76	72
Acquisitions of property and equipment	(17)	(11)
Acquisition of subsidiary, net of cash acquired	0	(183)
Net cash used in investing activities	(23)	(213)
Financing activities
Repurchase of common stock	(91)	(350)
Revolver drawdown	495	0
Revolver repayment	(200)	0
Awards effectively repurchased for required employee withholding taxes	(4)	(3)
Net cash provided by (used in) financing activities	200	(353)
Net increase (decrease) in cash and cash equivalents, unrestricted and restricted	100	(352)
Cash and cash equivalents, unrestricted and restricted:
Beginning of period	1,537	1,738
End of period	1,637	1,386
Supplemental disclosures of cash flow information
Interest paid	11	9
Income taxes (refund) paid, net	4	(12)
Supplemental schedule of noncash investing and financing activities
Payable for purchase of property and equipment	$ 5	$ 4