Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2013
Policy
Principles of Consolidation	Principles of Consolidation and Reporting These unaudited condensed consolidated financial statements include the accounts of Northrop Grumman Corporation and subsidiaries (herein referred to as "Northrop Grumman," the "company," "we," "us," or "our"). All material intercompany accounts, transactions, and profits are eliminated in consolidation. Investments in equity securities and joint ventures where the company has significant influence, but not control, are accounted for using the equity method.
Basis of Presentation	The accompanying unaudited condensed consolidated financial statements of the company have been prepared by management in accordance with the rules of the Securities and Exchange Commission (SEC) for interim reporting purposes. These statements include all adjustments of a normal recurring nature considered necessary by management for a fair presentation of the company's consolidated financial position, results of operations, and cash flows. The results reported in these financial statements are not necessarily indicative of results that may be expected for the entire year. These financial statements should be read in conjunction with the information contained in the company’s Annual Report on Form 10-K for the year ended December 31, 2012 (2012 Annual Report on Form 10-K).
Fiscal Period Policy	The quarterly information is labeled using a calendar convention; that is, first quarter is consistently labeled as ending on March 31, second quarter as ending on June 30, and third quarter as ending on September 30. It is management’s long-standing practice to establish actual interim closing dates using a “fiscal” calendar, in which we close our books on a Friday near these quarter-end dates in order to normalize the potentially disruptive effects of quarterly closings on business processes. This practice is only used at interim periods within a reporting year.
Accounting Estimates	Accounting Estimates The accompanying unaudited condensed consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). The preparation thereof requires management to make estimates and judgments that affect the reported amounts of assets and liabilities and the disclosure of contingencies at the date of the financial statements, as well as the reported amounts of revenues and expenses during the reporting period. Estimates have been prepared using the most current and best available information; however, actual results could differ materially from those estimates.
Revenue Recognition, Long-term Contracts	The majority of our contracts are accounted for under the percentage-of-completion method. For such contracts, changes in estimates of contract sales, costs, or profits are recognized using the cumulative catch-up method of accounting. This method recognizes, in the current period, the cumulative effect of the changes on current and prior periods, and revenue and profit on future periods of contract performance are recognized as if the revised estimate had been used since contract inception. Changes in contract estimates occur for a variety of reasons, including changes in contract scope, estimated revenue and cost estimates. These changes are often driven by events such as changes in estimated incentive fees, unanticipated risks affecting contract costs, the resolution of risk at lower or higher cost than anticipated, and changes in indirect cost allocations, such as overhead and general and administrative expenses. We employ an extensive contract management process involving several functional organizations and numerous personnel who are skilled at managing contract activities. Changes in estimates are frequent; the company performs on a broad portfolio of long-term contracts, many of which include complex and customized aerospace and electronic equipment and software, that often includes technology at the forefront of science.
Pension and Other Postretirement Plans	Net actuarial gains or losses are re-determined annually and principally arise from changes in the rate used to discount the benefit obligations and differences in expected and actual returns on plan assets.
Comprehensive Income	Reclassifications for cumulative translation adjustments and marketable securities are recorded in other income, and reclassifications for effective cash flow hedges are recorded in operating income.
Earnings Per Share	We calculate basic earnings per share by dividing net earnings by the weighted-average number of shares of common stock outstanding during each period. Diluted earnings per share includes the dilutive effect of awards granted to employees under stock-based compensation plans.
Income Taxes	The company recognizes accrued interest and penalties related to uncertain tax positions in federal and foreign income tax expense.
Investments in Marketable Securities	Investments in Marketable Securities The company holds a portfolio of marketable securities to partially fund long-term deferred compensation programs. The portfolio consists of equity securities that are classified as either trading or available-for-sale, which can be liquidated without restriction. These assets are recorded at fair value and are valued using Level 1 inputs.
Long-term Debt, Fair Value	Long-term Debt The fair value of long-term debt is calculated using Level 2 inputs based on interest rates available for debt with terms and maturities similar to the company’s existing debt arrangements.
Guarantees of Subsidiary Performance Obligations	Guarantees of Subsidiary Performance Obligations From time to time in the ordinary course of business, the company guarantees obligations of its subsidiaries under certain contracts. Generally, the company is liable under such an arrangement only if its subsidiary is unable to perform under its contract. Historically, the company has not incurred any substantial liabilities resulting from these guarantees. In addition, the company’s subsidiaries may enter into joint ventures, teaming and other business arrangements (collectively, Business Arrangements) to support the company’s products and services in domestic and international markets. The company generally strives to limit its exposure under these arrangements to its subsidiary’s investment in the Business Arrangements or to the extent of such subsidiary’s obligations under the applicable contract. In some cases, however, the company may be required to guarantee the performance of the Business Arrangements and, in such cases, the company generally obtains cross-indemnification from the other members of the Business Arrangements.
U.S. Government Cost Claims	U.S. Government Cost Claims From time to time, the company is advised of claims by the U.S. Government concerning certain potential disallowed costs, plus, at times, penalties and interest. When such findings are presented, the company and the U.S. Government representatives engage in discussions to enable the company to evaluate the merits of these claims, as well as to assess the amounts being claimed. Where appropriate, provisions are made to reflect the company’s expected exposure to the matters raised by the U.S. Government. Such provisions are reviewed on a quarterly basis for sufficiency based on the most recent information available.
Derivative Policy 1
Policy
Derivative Financial Instruments and Hedging Activities	Derivative Financial Instruments and Hedging Activities The company's derivative portfolio consists primarily of foreign currency forward contracts.
Derivative Policy 2
Policy
Derivative Financial Instruments and Hedging Activities	Derivative financial instruments are recognized as assets or liabilities in the financial statements and measured at fair value. Substantially all of these instruments are valued using Level 2 inputs. Unrealized gains or losses on the effective portion of cash flow hedges are reclassified from other comprehensive income to operating income upon the settlement of the underlying transactions.
Derivative Policy 3
Policy
Derivative Financial Instruments and Hedging Activities	Hedge contracts not designated for hedge accounting and the ineffective portion of cash flow hedges are recorded in other income.
Environmental Policy 1
Policy
Environmental Matters	Environmental Matters The company has been named a Potentially Responsible Party by the Environmental Protection Agency or similarly designated state or local agencies at certain current or formerly owned or leased sites. The estimated cost to complete remediation has been accrued where the company believes, based on the facts and circumstances known to the company, it is probable the company will incur costs to address environmental impacts.
Environmental Policy 2
Policy
Environmental Matters	A portion of the environmental remediation costs is expected to be recoverable through overhead charges on government contracts and, accordingly, such amounts are deferred in inventoried costs and other non-current assets.
Environmental Policy 3
Policy
Environmental Matters	These amounts are evaluated for recoverability on a routine basis.

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2013

Principles of Consolidation and Reporting

These unaudited condensed consolidated financial statements include the accounts of Northrop Grumman Corporation and subsidiaries (herein referred to as "Northrop Grumman," the "company," "we," "us," or "our"). All material intercompany accounts, transactions, and profits are eliminated in consolidation. Investments in equity securities and joint ventures where the company has significant influence, but not control, are accounted for using the equity method.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements of the company have been prepared by management in accordance with the rules of the Securities and Exchange Commission (SEC) for interim reporting purposes. These statements include all adjustments of a normal recurring nature considered necessary by management for a fair presentation of the company's consolidated financial position, results of operations, and cash flows.

The results reported in these financial statements are not necessarily indicative of results that may be expected for the entire year. These financial statements should be read in conjunction with the information contained in the company’s Annual Report on Form 10-K for the year ended December 31, 2012 (2012 Annual Report on Form 10-K).

Fiscal Period Policy

The quarterly information is labeled using a calendar convention; that is, first quarter is consistently labeled as ending on March 31, second quarter as ending on June 30, and third quarter as ending on September 30. It is management’s long-standing practice to establish actual interim closing dates using a “fiscal” calendar, in which we close our books on a Friday near these quarter-end dates in order to normalize the potentially disruptive effects of quarterly closings on business processes. This practice is only used at interim periods within a reporting year.

Accounting Estimates

The accompanying unaudited condensed consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). The preparation thereof requires management to make estimates and judgments that affect the reported amounts of assets and liabilities and the disclosure of contingencies at the date of the financial statements, as well as the reported amounts of revenues and expenses during the reporting period. Estimates have been prepared using the most current and best available information; however, actual results could differ materially from those estimates.

Revenue Recognition, Long-term Contracts

The majority of our contracts are accounted for under the percentage-of-completion method. For such contracts, changes in estimates of contract sales, costs, or profits are recognized using the cumulative catch-up method of accounting. This method recognizes, in the current period, the cumulative effect of the changes on current and prior periods, and revenue and profit on future periods of contract performance are recognized as if the revised estimate had been used since contract inception. Changes in contract estimates occur for a variety of reasons, including changes in contract scope, estimated revenue and cost estimates. These changes are often driven by events such as changes in estimated incentive fees, unanticipated risks affecting contract costs, the resolution of risk at lower or higher cost than anticipated, and changes in indirect cost allocations, such as overhead and general and administrative expenses. We employ an extensive contract management process involving several functional organizations and numerous personnel who are skilled at managing contract activities. Changes in estimates are frequent; the company performs on a broad portfolio of long-term contracts, many of which include complex and customized aerospace and electronic equipment and software, that often includes technology at the forefront of science.

Pension and Other Postretirement Plans

Net actuarial gains or losses are re-determined annually and principally arise from changes in the rate used to discount the benefit obligations and differences in expected and actual returns on plan assets.

Comprehensive Income

Reclassifications for cumulative translation adjustments and marketable securities are recorded in other income, and reclassifications for effective cash flow hedges are recorded in operating income.

Earnings Per Share

We calculate basic earnings per share by dividing net earnings by the weighted-average number of shares of common stock outstanding during each period.

Diluted earnings per share includes the dilutive effect of awards granted to employees under stock-based compensation plans.

Income Taxes

The company recognizes accrued interest and penalties related to uncertain tax positions in federal and foreign income tax expense.

Investments in Marketable Securities

The company holds a portfolio of marketable securities to partially fund long-term deferred compensation programs. The portfolio consists of equity securities that are classified as either trading or available-for-sale, which can be liquidated without restriction. These assets are recorded at fair value and are valued using Level 1 inputs.

Long-term Debt, Fair Value

Long-term Debt

The fair value of long-term debt is calculated using Level 2 inputs based on interest rates available for debt with terms and maturities similar to the company’s existing debt arrangements.

Guarantees of Subsidiary Performance Obligations

From time to time in the ordinary course of business, the company guarantees obligations of its subsidiaries under certain contracts. Generally, the company is liable under such an arrangement only if its subsidiary is unable to perform under its contract. Historically, the company has not incurred any substantial liabilities resulting from these guarantees.

In addition, the company’s subsidiaries may enter into joint ventures, teaming and other business arrangements (collectively, Business Arrangements) to support the company’s products and services in domestic and international markets. The company generally strives to limit its exposure under these arrangements to its subsidiary’s investment in the Business Arrangements or to the extent of such subsidiary’s obligations under the applicable contract. In some cases, however, the company may be required to guarantee the performance of the Business Arrangements and, in such cases, the company generally obtains cross-indemnification from the other members of the Business Arrangements.

U.S. Government Cost Claims

From time to time, the company is advised of claims by the U.S. Government concerning certain potential disallowed costs, plus, at times, penalties and interest. When such findings are presented, the company and the U.S. Government representatives engage in discussions to enable the company to evaluate the merits of these claims, as well as to assess the amounts being claimed. Where appropriate, provisions are made to reflect the company’s expected exposure to the matters raised by the U.S. Government. Such provisions are reviewed on a quarterly basis for sufficiency based on the most recent information available.

Derivative Policy 1

Policy

Derivative Financial Instruments and Hedging Activities

The company's derivative portfolio consists primarily of foreign currency forward contracts.

Derivative Policy 2

Policy

Derivative Financial Instruments and Hedging Activities

Derivative financial instruments are recognized as assets or liabilities in the financial statements and measured at fair value. Substantially all of these instruments are valued using Level 2 inputs.

Unrealized gains or losses on the effective portion of cash flow hedges are reclassified from other comprehensive income to operating income upon the settlement of the underlying transactions.

Derivative Policy 3

Policy

Derivative Financial Instruments and Hedging Activities

Hedge contracts not designated for hedge accounting and the ineffective portion of cash flow hedges are recorded in other income.

Environmental Policy 1

Policy

Environmental Matters

The company has been named a Potentially Responsible Party by the Environmental Protection Agency or similarly designated state or local agencies at certain current or formerly owned or leased sites. The estimated cost to complete remediation has been accrued where the company believes, based on the facts and circumstances known to the company, it is probable the company will incur costs to address environmental impacts.

Environmental Policy 2

Policy

Environmental Matters

A portion of the environmental remediation costs is expected to be recoverable through overhead charges on government contracts and, accordingly, such amounts are deferred in inventoried costs and other non-current assets.

Environmental Policy 3

Policy

Environmental Matters

These amounts are evaluated for recoverability on a routine basis.