Segment Information - Summary of Reconciliation Operating Income to EBITDA (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net revenues	$ 1,771	$ 1,649	$ 3,385	$ 3,120
EBITDA Reconciliation
Operating income (loss)	107	59	180	52
Plus:
Investment income and other, net	3	2	5	2
Non-service pension benefit	3	11	6	22
Loss on extinguishment of debt, net			(3)
Depreciation	19	19	38	38
Amortization	56	57	111	114
EBITDA	188	148	337	228
Total assets	7,974	8,054	7,974	8,054	$ 8,091
Capital expenditures	25	22	46	34
Safety Services [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net revenues	1,225	1,146	2,416	2,220
EBITDA Reconciliation
Operating income (loss)	98	63	194	126
Plus:
Investment income and other, net		1		1
Non-service pension benefit	3	11	6	22
Depreciation	7	5	13	12
Amortization	42	41	83	83
EBITDA	150	121	296	244
Total assets	6,107	6,156	6,107	6,156
Capital expenditures	9	5	14	11
Specialty Services [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net revenues	555	518	985	930
EBITDA Reconciliation
Operating income (loss)	41	32	41	25
Plus:
Investment income and other, net	3	2	5	3
Depreciation	12	11	24	23
Amortization	13	15	26	29
EBITDA	69	60	96	80
Total assets	1,328	1,305	1,328	1,305
Capital expenditures	16	15	31	21
Corporate and Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net revenues	(9)	(15)	(16)	(30)
EBITDA Reconciliation
Operating income (loss)	(32)	(36)	(55)	(99)
Plus:
Investment income and other, net		(1)		(2)
Loss on extinguishment of debt, net			(3)
Depreciation		3	1	3
Amortization	1	1	2	2
EBITDA	(31)	(33)	(55)	(96)
Total assets	$ 539	593	539	593
Capital expenditures		$ 2	$ 1	$ 2