COMMITMENTS AND CONTINGENCIES

Contract Performance Contingencies - Contract profit margins may include estimates of revenues for matters on which the customer and the Company have not reached agreement, such as settlements in the process of negotiation, contract changes, claims, and requests for equitable adjustment for previously unanticipated contract costs. These estimates are based upon management's best assessment of the underlying causal events and circumstances, and are included in determining contract profit margins to the extent of expected recovery based on contractual entitlements and the probability of successful negotiation with the customer. As of December 31, 2017, recognized amounts related to claims and requests for equitable adjustment were not material individually or in aggregate.

Guarantees of Performance Obligations - From time to time in the ordinary course of business, HII may enter into joint ventures, teaming, and other business arrangements to support the Company's products and services. The Company generally strives to limit its exposure under these arrangements to its investment or the extent of obligations under the applicable contract. In some cases, however, HII may be required to guarantee performance of the arrangement's obligations and, in such cases, generally obtains cross-indemnification from the other members of the arrangement.

In the ordinary course of business, the Company may guarantee obligations of its subsidiaries under certain contracts. Generally, the Company is liable under such an arrangement only if its subsidiary is unable to perform its obligations. Historically, the Company has not incurred any substantial liabilities resulting from these guarantees. As of December 31, 2017, the Company was not aware of any existing event of default that would require it to satisfy any of these guarantees.

Environmental Matters - The estimated cost to complete environmental remediation has been accrued where it is probable that the Company will incur such costs in the future to address environmental conditions at currently or formerly owned or leased operating facilities, or at sites where it has been named a Potentially Responsible Party ("PRP") by the Environmental Protection Agency or similarly designated by another environmental agency, and the related costs can be estimated by management. These accruals do not include any litigation costs related to environmental matters, nor do they include amounts recorded as asset retirement obligations. To assess the potential impact on the Company's consolidated financial statements, management estimates the range of reasonably possible remediation costs that could be incurred by the Company, taking into account currently available facts on each site, as well as the current state of technology and prior experience in remediating contaminated sites. These estimates are reviewed periodically and adjusted to reflect changes in facts and technical and legal circumstances. Management estimates that as of December 31, 2017, the probable future cost for environmental remediation was $1 million, which is accrued in other current liabilities. Factors that could result in changes to the Company's estimates include: modification of planned remedial actions, increases or decreases in the estimated time required to remediate, changes to the determination of legally responsible parties, discovery of more extensive contamination than anticipated, changes in laws and regulations affecting remediation requirements, and improvements in remediation technology. Should other PRPs not pay their allocable shares of remediation costs, the Company may incur costs exceeding those already estimated and accrued. Although management cannot predict whether new information gained as projects progress will materially affect the estimated liability accrued, management does not believe that future remediation expenditures will have a material effect on the Company's consolidated financial position, results of operations, or cash flows. In addition, there are certain potential remediation sites where the costs of remediation cannot be reasonably estimated.

Financial Arrangements - In the ordinary course of business, HII uses standby letters of credit issued by commercial banks and surety bonds issued by insurance companies primarily to support the Company's self-insured workers' compensation plans. As of December 31, 2017, the Company had $15 million in standby letters of credit issued but undrawn, as indicated in Note 14: Debt, and $258 million of surety bonds outstanding.

U.S. Government Claims - From time to time, the U.S. Government communicates to the Company potential claims, disallowed costs, and penalties concerning prior costs incurred by the Company with which the U.S. Government disagrees. When such preliminary findings are presented, the Company and U.S. Government representatives engage in discussions, from which HII evaluates the merits of the claims and assesses the amounts being questioned. Although the Company believes that the resolution of any of these matters will not have a material effect on its consolidated financial position, results of operations, or cash flows, it cannot predict the ultimate outcome of these matters.

Collective Bargaining Agreements - Of the Company's approximately 38,000 employees, approximately 50% are covered by a total of nine collective bargaining agreements and two site stabilization agreements. Newport News has four collective bargaining agreements covering represented employees, one of which covers approximately 50% of Newport News employees and was renewed July 2017. The remaining collective bargaining agreements at Newport News expire August 2018, December 2018, and November 2020. Newport News craft workers employed at the Kesselring Site near Saratoga Springs, New York are represented under an indefinite Department of Energy ("DoE") site agreement. Ingalls has five collective bargaining agreements covering represented employees, all of which expire in March 2022. Approximately 35 Technical Solutions craft employees at the Hanford Site near Richland, Washington are represented under an indefinite DoE site stabilization agreement. The Company believes its relationship with its employees is satisfactory.

Collective bargaining agreements generally expire after three to five years and are subject to renegotiation at that time. The Company does not expect the results of these negotiations, either individually or in the aggregate, to have a material effect on the Company's consolidated results of operations.

Purchase Obligations - Periodically the Company enters into agreements to purchase goods or services that are enforceable and legally binding on the Company and specify all significant terms, including: fixed or minimum quantities to be purchased; fixed, minimum, or variable price provisions; and the approximate timing of the transaction. These obligations are primarily comprised of open purchase order commitments to vendors and subcontractors pertaining to funded contracts.

Operating Leases - Rental expense for operating leases for the years ended December 31, 2017, 2016, and 2015, was $63 million, $69 million, and $62 million, respectively. These amounts are net of immaterial amounts of sublease rental income. The amounts of minimum rental commitments under long-term non-cancellable operating leases for each of the years 2018 through 2022 and thereafter are:



($ in millions)
2018	$	39
2019	35
2020	28
2021	24
2022	17
Thereafter	51
Total	$	194