Accrued Workers' Compensation Costs - Summary of Workers' Compensation Loss Reserve Activity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Total accrued costs, beginning of period	$ 189	$ 198	$ 198	$ 205
Incurred
Current year	18	16	51	49
Prior years	(3)	(3)	(23)	(18)
Total incurred	15	13	28	31
Paid
Current year	(4)	(3)	(6)	(6)
Prior years	(8)	(10)	(28)	(32)
Total paid	(12)	(13)	(34)	(38)
Total accrued costs, end of period	$ 192	$ 198	$ 192	$ 198