Accrued Workers' Compensation Costs - Summary of Workers' Compensation Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Insurance [Abstract]
Total accrued costs, end of period	$ 199	$ 198	$ 205	$ 205
Collateral paid to carriers and offset against accrued costs	(8)	(8)
Total accrued costs, net of carrier collateral offset	191	190
Payable in less than 1 year (net of collateral paid to carriers)	48	55
Payable in more than 1 year (net of collateral paid to carriers)	143	135
Total accrued costs, net of carrier collateral offset	191	190
Net of collateral paid to carriers, payable in less than one year	(2)	(2)
Net of collateral paid to carriers, payable in more than 1 year	$ (6)	$ (6)