Segment Information - Summary of Reconciliation Operating Income to EBITDA (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net revenues	$ 1,649	$ 978	$ 3,120	$ 1,781
EBITDA Reconciliation
Operating income (loss)	59	47	52	45
Plus:
Investment income and other, net	2	6	2	9
Loss on extinguishment of debt		(9)		(9)
Non-service pension benefit	11		22
Depreciation	19	20	38	39
Amortization	57	32	114	63
EBITDA	148	96	228	147
Total assets	8,054	4,243	8,054	4,243	$ 5,159
Capital expenditures	22	16	34	34
Safety Services [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net revenues	1,146	512	2,220	978
EBITDA Reconciliation
Operating income (loss)	63	52	126	97
Plus:
Investment income and other, net	1	2	1	5
Non-service pension benefit	11		22
Depreciation	5	1	12	3
Amortization	41	18	83	33
EBITDA	121	73	244	138
Total assets	6,156	2,141	6,156	2,141
Capital expenditures	5	1	11	2
Specialty Services [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net revenues	518	476	930	820
EBITDA Reconciliation
Operating income (loss)	32	24	25	6
Plus:
Investment income and other, net	2	3	3	4
Depreciation	11	17	23	33
Amortization	15	14	29	29
EBITDA	60	58	80	72
Total assets	1,305	1,285	1,305	1,285
Capital expenditures	15	15	21	32
Corporate and Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net revenues	(15)	(10)	(30)	(17)
EBITDA Reconciliation
Operating income (loss)	(36)	(29)	(99)	(58)
Plus:
Investment income and other, net	(1)	1	2
Loss on extinguishment of debt		(9)		(9)
Depreciation	3	2	3	3
Amortization	1		2	1
EBITDA	(33)	(35)	(96)	(63)
Total assets	593	$ 817	593	$ 817
Capital expenditures	$ 2		$ 2