INCOME TAXES - Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating losses (federal and state)	$ 3	$ 3
Accrued expenses	20	14
Accrued workers' compensation costs	9	9
Recovery credit	13	26
Operating lease liabilities	13	15
Stock based compensation	3	3
Tax benefits relating to uncertain positions	1	1
Tax credits (federal and state)	6	8
Total	68	79
Valuation allowance	(5)	(5)	$ (5)	$ (7)
Total deferred tax assets	63	74
Deferred tax liabilities:
Depreciation and amortization	(37)	(37)
Deferred service revenues	0	(20)
Prepaid commission expenses	(24)	(22)
Operating lease right-of-use assets	(10)	(13)
Other	(1)	(2)
Total deferred tax liabilities	(72)	(94)
Net deferred tax liabilities	$ (9)	$ (20)