Segment Information - Summary of Reconciliation Operating Income to EBITDA (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net revenues	$ 1,471	$ 803
EBITDA Reconciliation
Operating income (loss)	(7)	(2)
Plus:
Investment income and other, net		3
Non-service pension benefit	11	0
Depreciation	19	19
Amortization	57	31
EBITDA	80	51
Total assets	8,142	4,218	$ 5,159
Capital expenditures	12	18
Safety Services [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net revenues	1,074	466
EBITDA Reconciliation
Operating income (loss)	63	45
Plus:
Investment income and other, net		3
Non-service pension benefit	11
Depreciation	7	2
Amortization	42	15
EBITDA	123	65
Total assets	6,423	2,122
Capital expenditures	6	1
Specialty Services [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net revenues	412	344
EBITDA Reconciliation
Operating income (loss)	(7)	(18)
Plus:
Investment income and other, net	1	1
Non-service pension benefit
Depreciation	12	16
Amortization	14	15
EBITDA	20	14
Total assets	1,254	1,236
Capital expenditures	6	17
Corporate and Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net revenues	(15)	(7)
EBITDA Reconciliation
Operating income (loss)	(63)	(29)
Plus:
Investment income and other, net	(1)	(1)
Non-service pension benefit
Depreciation		1
Amortization	1	1
EBITDA	(63)	(28)
Total assets	465	860
Capital expenditures