Under ASC 606, Revenue from Contracts with Customers (“ASC 606”), revenue is recognized when, or as, control of promised goods and services is transferred to customers, and the amount of revenue recognized reflects the consideration to which an entity expects to be entitled in exchange for the goods and services transferred. Revenue is primarily recognized by the Company over time utilizing the cost-to-cost measure of progress, consistent with the Company’s previous revenue recognition practices. Revenue recognized at a point in time relates primarily to distribution contracts and was not material for the three and nine months ended September 30, 2020 (Successor) and 2019 (Predecessor), respectively.

Contracts with customers: The Company derives revenue primarily from Safety Services, Specialty Services and Industrial Services contracts with a duration of less than one week to three years, with the majority of contracts with durations of less than six months, which are subject to multiple pricing options, including fixed price, unit price, time and materials, or cost plus a markup. The Company also enters into fixed-price service contracts related to monitoring, maintenance and inspection of safety systems. The Company may utilize subcontractors in the fulfillment of its performance obligations. When doing so, the Company is considered the principal in these transactions and revenue is recognized on a gross basis.

Revenue for fixed-price agreements is generally recognized over time using the cost-to-cost method of accounting, which measures progress based on the cost incurred to total expected cost in satisfying its performance obligation. The cost-to-cost method is used as it best depicts the continuous transfer of control of goods or services to the customer. Costs incurred include direct materials, labor and subcontract costs, and indirect costs related to contract performance, such as indirect labor, supplies, tools, repairs and depreciation costs. These contract costs are included in the results of operations under cost of revenues. Labor costs are considered to be incurred as the work is performed. Subcontractor labor is recognized as the work is performed.

Revenue from time and material contracts is recognized as the services are provided and is equal to the sum of the contract costs incurred plus an agreed upon markup. Revenue earned from distribution contracts is recognized upon shipment or performance of the service.

The cost estimation process for recognizing revenue over time under the cost-to-cost method is based on the professional knowledge and experience of the Company’s project managers, engineers and financial professionals. Management reviews estimates of total contract transaction price and total project costs on an ongoing basis. Changes in job performance, job conditions and management’s assessment of expected variable consideration are factors that influence estimates of the total contract transaction price, total costs to complete those contracts and the Company’s profit recognition. Changes in these factors could result in cumulative revisions to revenue in the period in which the revisions are determined, which could materially affect the Company’s consolidated results of operations for that period. Provisions for estimated losses on uncompleted contracts are recorded in the period in which such estimated losses are determined.

The Company disaggregates its revenue primarily by segment, service type, and country from which revenue is invoiced, as the nature, timing and uncertainty of cash flows are relatively consistent within each of these categories. Disaggregated revenue information is as follows:

	Three Months Ended September 30, 2020 (Successor)
	Safety Services		Specialty Services		Industrial Services		Corporate and Eliminations			Consolidated
Life Safety	$	322	$	—	$	—	$	—		$	322
Mechanical		82		—		—		—			82
Infrastructure/Utility		—		230		—		—			230
Fabrication		—		58		—		—			58
Specialty Contracting		—		112		—		—			112
Transmission		—		—		127		—			127
Civil		—		—		25		—			25
Inspection		—		—		6		—			6
Corporate and Eliminations		—		—		—		(4	)		(4	)
Net revenues	$	404	$	400	$	158	$	(4	)	$	958

	Three Months Ended September 30, 2019 (Predecessor)
	Safety Services		Specialty Services		Industrial Services		Corporate and Eliminations			Consolidated
Life safety	$	363	$	—	$	—	$	—		$	363
Mechanical		109		—		—		—			109
Infrastructure/Utility		—		241		—		—			241
Fabrication		—		44		—		—			44
Specialty Contracting		—		122		—		—			122
Transmission		—		—		156		—			156
Civil		—		—		29		—			29
Inspection		—		—		60		—			60
Corporate and Eliminations		—		—		—		(6	)		(6	)
Net revenues	$	472	$	407	$	245	$	(6	)	$	1,118

	Nine Months Ended September 30, 2020 (Successor)
	Safety Services		Specialty Services		Industrial Services		Corporate and Eliminations			Consolidated
Life Safety	$	963	$	—	$	—	$	—		$	963
Mechanical		236		—		—		—			236
Infrastructure/Utility		—		615		—		—			615
Fabrication		—		129		—		—			129
Specialty Contracting		—		305		—		—			305
Transmission		—		—		336		—			336
Civil		—		—		50		—			50
Inspection		—		—		82		—			82
Corporate and Eliminations		—		—		—		(11	)		(11	)
Net revenues	$	1,199	$	1,049	$	468	$	(11	)	$	2,705

	Nine Months Ended September 30, 2019 (Predecessor)
	Safety Services		Specialty Services		Industrial Services		Corporate and Eliminations			Consolidated
Life Safety	$	1,038	$	—	$	—	$	—		$	1,038
Mechanical		304		—		—		—			304
Infrastructure/Utility		—		645		—		—			645
Fabrication		—		114		—		—			114
Specialty Contracting		—		348		—		—			348
Transmission		—		—		443		—			443
Civil		—		—		45		—			45
Inspection		—		—		182		—			182
Corporate and Eliminations		—		—		—		(12	)		(12	)
Net revenues	$	1,342	$	1,107	$	670	$	(12	)	$	3,107

	Three Months Ended September 30, 2020 (Successor)
	Safety Services		Specialty Services		Industrial Services		Corporate and Eliminations			Consolidated
United States	$	361	$	400	$	144	$	(4	)	$	901
Canada and United Kingdom		43		—		14		—			57
Net revenues	$	404	$	400	$	158	$	(4	)	$	958

	Three Months Ended September 30, 2019 (Predecessor)
	Safety Services		Specialty Services		Industrial Services		Corporate and Eliminations			Consolidated
United States	$	416	$	407	$	233	$	(6	)	$	1,050
Canada and United Kingdom		56		—		12		—			68
Net revenues	$	472	$	407	$	245	$	(6	)	$	1,118

	Nine Months Ended September 30, 2020 (Successor)
	Safety Services		Specialty Services		Industrial Services		Corporate and Eliminations			Consolidated
United States	$	1,074	$	1,049	$	445	$	(11	)	$	2,557
Canada and United Kingdom		125		—		23		—			148
Net revenues	$	1,199	$	1,049	$	468	$	(11	)	$	2,705

	Nine Months Ended September 30, 2019 (Predecessor)
	Safety Services		Specialty Services		Industrial Services		Corporate and Eliminations			Consolidated
United States	$	1,185	$	1,107	$	603	$	(12	)	$	2,883
Canada and United Kingdom		157		—		67		—			224
Net revenues	$	1,342	$	1,107	$	670	$	(12	)	$	3,107

The Company’s contracts with its customers generally require significant services to integrate complex activities and equipment into a single deliverable, and are therefore generally accounted for as a single performance obligation to provide a single contracted service for the duration of the project. For contracts with multiple performance obligations, the transaction price of a contract is allocated to each performance obligation and recognized as revenue when or as the performance obligation is satisfied using the estimated stand-alone selling price of each distinct good or service. The stand-alone selling price is estimated using the expected cost plus a margin approach for each performance obligation. The aggregate amount of transaction price allocated to the performance obligations that are unsatisfied as of September 30, 2020, was $1,428.

When more than one contract is entered into with a customer on or close to the same date, management evaluates whether those contracts should be combined and accounted for as a single contract as well as whether those contracts should be accounted for as one, or more than one, performance obligation. This evaluation requires significant judgment and is based on the facts and circumstances of the various contracts.

Contracts are often modified through change orders to account for changes in the scope and price of the goods or services being provided. Although the Company evaluates each change order to determine whether such modification creates a separate performance obligation, the majority of change orders are for goods or services that are not distinct within the context of the original contract and, therefore, are not treated as separate performance obligations but rather as a modification of the existing contract and performance obligation.

Variable consideration: Transaction prices for customer contracts may include variable consideration, which comprises items such as early completion bonuses and liquidated damages provisions. Management estimates variable consideration for a performance obligation utilizing estimation methods that are believed to best predict the amount of consideration to which the Company will be entitled. Variable consideration is included in the transaction price only to the extent it is probable, in the Company’s judgment, that a significant future reversal in the amount of cumulative revenue recognized under the contract will not occur when the uncertainty associated with the variable consideration is subsequently resolved.

Changes in the estimates of transaction prices are recognized in revenue on a cumulative catch-up basis in the period in which the revisions to the estimates are made. Such changes in estimates may also result in the reversal of previously recognized revenue if the ultimate outcome differs from the Company’s previous estimate. For the three and nine months ended September 30, 2020 (Successor) and 2019 (Predecessor), the Company did not recognize significant revenue associated with the final settlement of contract value for any projects that were completed in prior periods. In addition, for the three and nine months ended September 30, 2020 (Successor) and 2019 (Predecessor), there were no significant reversals of revenue recognized associated with the revision of transaction prices. The Company typically does not incur any returns, refunds or similar obligations after the completion of the performance obligation since any deficiencies are corrected during the course of performance.

Contract assets and liabilities: The Company typically invoices customers with payment terms of net due in 30 days. It is also common for the contract in the industry to specify that a general contractor is not required to submit payments to a subcontractor until it has received those funds from the owner or funding source. In most instances, the Company receives payment of invoices between 30 to 90 days of the date of the invoice.

The timing of revenue recognition may differ from the timing of invoicing to customers. Contract assets include unbilled amounts from the Company’s projects when revenues recognized under the cost-to-cost measure of progress exceed the amounts invoiced to the Company’s customers, as the amounts cannot be billed under the terms of the Company’s contracts. In addition, many of the Company’s time and materials arrangements are billed in arrears pursuant to contract terms, resulting in contract assets being recorded, as revenue is recognized in advance of billings.

The Company utilizes the practical expedient under ASC 606 and does not adjust for a significant financing component if the time between payment and the transfer of the related good or service is expected to be one year or less. The Company’s revenue arrangements are typically accounted for under such expedient as payments are within one year of performance for the Company’s services. As of September 30, 2020, none of the Company’s contracts contained a significant financing component. Contract liabilities from the Company’s contracts arise when amounts invoiced to the Company’s customers exceed revenues recognized under the cost-to-cost measure of progress. Contract liabilities also include advance payments from the Company’s customers on certain contracts. Contract liabilities decrease as the Company recognizes revenue from the satisfaction of the related performance obligation. Contract assets and liabilities are classified as current in the consolidated balance sheets as all amounts are expected to be relieved within one year.

The opening and closing balances of accounts receivable, net of allowances, contract assets and contract liabilities from contracts with customers as of September 30, 2020 and December 31, 2019 are as follows:

The Company did not recognize significant revenue associated with the final settlement of contract value for any projects that were completed in prior periods. In accordance with industry practice, accounts receivable includes retentions receivable, a portion of which may not be received within one year. At September 30, 2020 and December 31, 2019, retentions receivable were $122 and $133, respectively, while the portions that may not be received within one year were $22 and $28, respectively. There were no other significant changes due to business acquisitions or significant changes in estimates of contract progress or transaction price. There was no significant impairment of contract assets recognized during the period.

Costs to obtain or fulfill a contract: The Company generally does not incur significant incremental costs related to obtaining or fulfilling a contract prior to the start of a project. The Company may incur certain fulfilment costs such as initial design or mobilization costs which are capitalized if: (i) they relate directly to the contract, (ii) are expected to generate resources that will be used to satisfy the Company’s performance obligation under the contract, and (iii) are expected to be recovered through revenue generated under the contract. Such costs, which are amortized over the life of the respective project, were not material for any period presented. The Company generally does not incur any significant costs related to obtaining a contract with a customer.