| **Significant Accounting Policies - Restructuring and Acquisition Related Charges (Details) - USD ($) $ / shares in Units, $ in Millions**        | 12 Months Ended |
|---------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|
||
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Restructuring charges                                                                                                                             | $ 48            |   |   |
| Liabilities of discontinued operations                                                                                                            | 30              | $ 28 |   |
| Restructuring charges, net of government cost reimbursment for severance and other employee-related exit costs                                    |            | 65 |   |
| Charges related to consolidation of facilities                                                                                                    |            | 14 |   |
| Change in operating income due to change in accounting estimate                                                                                   | $ 67            | $ 57 | $ 53 |
| Change in earnings per share due to change in accounting estimate (in dollars per share)                                                          | $ 0.33          | $ 0.37 | $ 0.33 |
| Communication Systems                                                                                                                             |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Restructuring charges, net of government cost reimbursment for severance and other employee-related exit costs                                    |            | $ 3 |   |
| Critical Networks                                                                                                                                 |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Restructuring charges                                                                                                                             | $ 13            |   |   |
| Restructuring charges, net of government cost reimbursment for severance and other employee-related exit costs                                    |            | 3 |   |
| Exelis                                                                                                                                            |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Restructuring charges, net of government cost reimbursment for severance and other employee-related exit costs                                    |            | 57 |   |
| Acquisition related charges                                                                                                                       | 115             | $ 281 |   |
| Exelis | 5.95% notes, due December 1, 2017                                                                                                        |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Interest rate on fixed rate debt (percent)                                                                                                        |            | 5.95% |   |
| Exelis | 6.375% notes, due June 15, 2019                                                                                                          |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Interest rate on fixed rate debt (percent)                                                                                                        |            | 6.375% |   |
| Exelis | Financing Costs                                                                                                                          |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Acquisition related charges                                                                                                                       |            | $ 146 |   |
| Exelis | Financing Costs | 5.95% notes, due December 1, 2017                                                                                      |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Acquisition related charges                                                                                                                       |            | 118 |   |
| Exelis | Financing Costs | Senior Unsecured Bridge Loan Facility                                                                                  |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Acquisition related charges                                                                                                                       |            | 18 |   |
| Exelis | Restructuring Charges                                                                                                                    |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Acquisition related charges                                                                                                                       |            | 65 |   |
| Exelis | Integration Costs                                                                                                                        |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Acquisition related charges                                                                                                                       |            | 34 |   |
| Exelis | Transaction Costs                                                                                                                        |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Acquisition related charges                                                                                                                       |            | 23 |   |
| Exelis | Other Costs Including Impairments Of Capitalized Software                                                                                |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Acquisition related charges                                                                                                                       |            | $ 13 |   |
| Exelis | Engineering, selling and administrative expenses                                                                                         |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed, Amortization of Step-up in Inventory | 11              |   |   |
| Discontinued Operations, Disposed of by Means Other than Sale                                                                                     |            |   |   |
| **Restructuring and Aquisition-Related Charges**                                                                                                  |            |   |   |
| Liabilities of discontinued operations                                                                                                            | $ 57            |   |   |

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| - Definition
For transactions that are recognized separately from the acquisition of assets and assumptions of liabilities in the business combination, such as related to pre-existing relationships with the acquiree, this element represents the disclosure of the amount of acquisition related costs which have been expensed.
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Contractual interest rate for funds borrowed, under the debt agreement.
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| - Definition
Amount classified as liabilities attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.
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| - Definition
Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.
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| - Definition
Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.
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