| **Business Segments**            | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      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| **Segment Reporting [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              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| Business Segments                | Business SegmentsWe structure our operations primarily around the products and services we sell and the markets we serve, and we report the financial results of our operations in the following four operating segments, which are also our reportable segments and are referred to as our business segments:•Communication Systems, serving markets in tactical communications and defense and public safety networks;•Space and Intelligence Systems, providing complete Earth observation, environmental, geospatial, space protection, and intelligence solutions from advanced sensors and payloads, as well as ground processing and information analytics;•Electronic Systems, offering an extensive portfolio of solutions in electronic warfare, avionics, wireless technology, command, control, communications, computers and intelligence and undersea systems; and•Critical Networks, providing managed services supporting air traffic management and ground network operation and sustainment, as well as high-value IT and engineering services.In the second quarter of fiscal 2017, we entered into a definitive agreement to sell our CapRock business. CapRock was formerly part of our Critical Networks segment and is reported as discontinued operations in this Report. As a result, our historical financial results have been restated to account for CapRock as discontinued operations for all periods presented in this Report. See Note B — Discontinued Operations in these Notes for additional information regarding discontinued operations. Except for disclosures related to our cash flows, or unless otherwise specified, disclosures in the accompanying Condensed Consolidated Financial Statements (Unaudited) and these Notes relate solely to our continuing operations.Beginning with the third quarter of fiscal 2017, we will report the financial results of our operations in the following three business segments: Communication Systems, Space and Intelligence Systems and Electronic Systems. See “Business Segments” under Note S — Subsequent Events in these Notes for additional information.The accounting policies of our business segments are the same as those described in Note 1: “Significant Accounting Policies” in our Notes to Consolidated Financial Statements in our Fiscal 2016 Form 10-K. We evaluate each segment’s performance based on its operating income or loss, which we define as profit or loss from operations before income taxes excluding interest income and expense, royalties and related intellectual property expenses, equity method investment income or loss and gains or losses from securities and other investments. Intersegment sales are generally transferred at cost to the buying segment, and the sourcing segment recognizes a profit that is eliminated. The “Corporate eliminations” line items in the tables below represent the elimination of intersegment sales and their related profits. The “Unallocated corporate expense” line item in the tables below represents the portion of corporate expenses not allocated to our business segments.Total assets by business segment are summarized below:  December 30, 2016 July 1, 2016       (In millions)Total Assets   Communication Systems$1,606 $1,667Space and Intelligence Systems2,119 2,149Electronic Systems2,241 2,253Critical Networks2,639 2,656Corporate (1) (2)3,013 3,268 $11,618 $11,993     (1)Identifiable intangible assets acquired in connection with our acquisition of Exelis Inc. (“Exelis”) in the fourth quarter of fiscal 2015 were recorded as Corporate assets because they benefit the entire Company as opposed to any individual segment. Exelis identifiable intangible asset balances recorded as Corporate assets were $1.4 billion as of December 30, 2016 and July 1, 2016.(2)Corporate assets include the assets and liabilities of discontinued operations. See Note B — Discontinued Operations in these Notes for additional information regarding discontinued operations.  Segment revenue, segment operating income and a reconciliation of segment operating income to total income from continuing operations before income taxes follow:  Quarter Ended Two Quarters Ended  December 30, 2016 January 1, 2016 December 30, 2016 January 1, 2016           (In millions)Revenue       Communication Systems$413 $489 $843 $943Space and Intelligence Systems468 446 921 881Electronic Systems384 381 745 756Critical Networks454 446 905 910Corporate eliminations(19) (14) (36) (32) $1,700 $1,748 $3,378 $3,458Income From Continuing Operations Before Income Taxes       Segment Operating Income:       Communication Systems (1)$121 $121 $240 $259Space and Intelligence Systems 77 68 157 135Electronic Systems79 63 153 132Critical Networks (2)75 63 135 123Unallocated corporate income (expense) (3)(65) 14 (135) (61)Corporate eliminations(1) (1) (2) (2)Non-operating income1 — 2 1Net interest expense(43) (46) (87) (92) $244 $282 $463 $495         (1)Communication Systems operating income included $17 million of charges in the quarter and two quarters ended January 1, 2016, primarily related to workforce reductions, facility consolidation and other items. We recorded $14 million of these charges in the “Cost of product sales and services” line item and the remaining $3 million of these charges in the “Engineering, selling and administrative expenses” line item in the accompanying Condensed Consolidated Statement of Income (Unaudited).(2)Critical Networks operating income included $4 million of charges in the quarter and two quarters ended January 1, 2016, primarily related to workforce reductions and facility consolidation. We recorded these charges in the “Engineering, selling and administrative expenses” line item in the accompanying Condensed Consolidated Statement of Income (Unaudited).(3)Unallocated corporate income (expense) included: (i) the impact of a net liability reduction of $101 million in the quarter and two quarters ended January 1, 2016 for certain post-employment benefit plans, (ii) charges of $13 million and $29 million in the quarter and two quarters ended December 30, 2016, respectively, compared with charges of $41 million and $61 million in the quarter and two quarters ended January 1, 2016, respectively, for integration and other costs associated with our acquisition of Exelis in the fourth quarter of fiscal 2015 and (iii) $33 million and $66 million of expense in the quarters and two quarters ended December 30, 2016 and January 1, 2016, respectively, for amortization of intangible assets acquired as a result of our acquisition of Exelis. Because the acquisition of Exelis benefited the entire Company as opposed to any individual segment, the amortization of identifiable intangible assets acquired in the Exelis acquisition was recorded as unallocated corporate expense. |

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| - Definition
The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.
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