DESCRIPTION OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES - Schedule of Assets and Liabilities of the Trust (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Current assets:
Cash and cash equivalents	$ 321	$ 360
Restricted cash, cash equivalents and investments	1,108	1,413
Total current assets	2,498	3,180
Total assets	3,425	4,119
Current liabilities:
Accounts payable and other current liabilities	89	89
Accrued wages	549	580
Payroll tax liabilities and other payroll withholdings	1,308	1,906
Total current liabilities	2,249	2,981
Total liabilities	3,315	$ 4,050
TriNet Trust
Current assets:
Cash and cash equivalents	3
Restricted cash, cash equivalents and investments	63
Total current assets	66
Total assets	66
Current liabilities:
Accounts payable and other current liabilities	1
Accrued wages	14
Payroll tax liabilities and other payroll withholdings	49
Total current liabilities	64
Total liabilities	$ 64