COMMITMENTS AND CONTINGENCIES

Litigation

Various claims and other legal proceedings incidental to the normal course of business are pending or threatened against us. These matters relate to such issues as government investigations and claims, the protection of the environment, asbestos-related claims and employee-related matters. The nature of litigation is such that we cannot predict the outcome of these matters. However, based on information currently available, we believe any potential liabilities in these proceedings, individually or in the aggregate, will not have a material impact on our results of operations, financial condition or cash flows.

Environmental

We are subject to and affected by a variety of federal, state, local and foreign environmental laws and regulations. We are directly or indirectly involved in environmental investigations or remediation at some of our current and former facilities and third-party sites that we do not own but where we have been designated a Potentially Responsible Party (PRP) by the U.S. Environmental Protection Agency or a state environmental agency. Based on historical experience, we expect that a significant percentage of the total remediation and compliance costs associated with these facilities will continue to be allowable contract costs and, therefore, recoverable under U.S. government contracts.

As required, we provide financial assurance for certain sites undergoing or subject to investigation or remediation. We accrue environmental costs when it is probable that a liability has been incurred and the amount can be reasonably estimated. Where applicable, we seek insurance recovery for costs related to environmental liabilities. We do not record insurance recoveries before collection is considered probable. Based on all known facts and analyses, we do not believe that our liability at any individual site, or in the aggregate, arising from such environmental conditions, will be material to our results of operations, financial condition or cash flows. We also do not believe that the range of reasonably possible additional loss beyond what has been recorded would be material to our results of operations, financial condition or cash flows.

Minimum Lease Payments

Total expense under operating leases was $283 in 2015, $297 in 2014 and $309 in 2013. Operating leases are primarily for facilities and equipment. Future minimum lease payments are as follows:



Year Ended December 31
2016	$	220
2017	179
2018	136
2019	90
2020	90
Thereafter	322
Total minimum lease payments	$	1,037

Other

Government Contracts. As a government contractor, we are subject to U.S. government audits and investigations relating to our operations, including claims for fines, penalties and compensatory and treble damages. We believe the outcome of such ongoing government audits and investigations will not have a material impact on our results of operations, financial condition or cash flows.

In the performance of our contracts, we routinely request contract modifications that require additional funding from the customer. Most often, these requests are due to customer-directed changes in the scope of work. While we are entitled to recovery of these costs under our contracts, the administrative process with our customer may be protracted. Based upon the circumstances, we periodically file requests for equitable adjustment (REAs) that are sometimes converted into claims. In some cases, these requests are disputed by our customer. We believe our outstanding modifications, REAs and other claims will be resolved without material impact to our results of operations, financial condition or cash flows.

Letters of Credit and Guarantees. In the ordinary course of business, we have entered into letters of credit, bank guarantees, surety bonds and other similar arrangements with financial institutions and insurance carriers totaling approximately $1.1 billion on December 31, 2015. In addition, from time to time and in the ordinary course of business, we contractually guarantee the payment or performance obligations of our subsidiaries arising under certain contracts.

Aircraft Trade-ins. In connection with orders for new aircraft in funded contract backlog, our Aerospace group has outstanding options with some customers to trade in aircraft as partial consideration in their new-aircraft transaction. These trade-in commitments are structured to establish the fair market value of the trade-in aircraft at a date generally 45 or fewer days preceding delivery of the new aircraft to the customer. At that time, the customer is required to either exercise the option or allow its expiration. Any excess of the pre-established trade-in price above the fair market value at the time the new outfitted aircraft is delivered is treated as a reduction of revenue in the new-aircraft sales transaction.

Labor Agreements. Approximately one-fifth of the employees of our subsidiaries work under collectively-bargained terms and conditions, including 53 collective agreements that we have negotiated directly with unions and works councils. A number of these agreements expire within any given year. Historically, we have been successful at renegotiating these labor agreements without any material disruption of operating activities. In 2016, we expect to negotiate the terms of 18 agreements covering approximately 6,400 employees. We do not expect the renegotiations will, either individually or in the aggregate, have a material impact on our results of operations, financial condition or cash flows.

Product Warranties. We provide warranties to our customers associated with certain product sales. We record estimated warranty costs in the period in which the related products are delivered. The warranty liability recorded at each balance sheet date is generally based on the number of months of warranty coverage remaining for the products delivered and the average historical monthly warranty payments. Warranty obligations incurred in connection with long-term production contracts are accounted for within the contract estimates at completion. Our other warranty obligations, primarily for business-jet aircraft, are included in other current and noncurrent liabilities on the Consolidated Balance Sheets.

The changes in the carrying amount of warranty liabilities for each of the past three years were as follows:



Year Ended December 31	2015			2014			2013
Beginning balance	$	428		$	354		$	316
Warranty expense	158			146			125
Payments	(120		)	(78		)	(82		)
Adjustments	(1		)	6			(5		)
Ending balance	$	465		$	428		$	354