Retirement Benefits (Details 7)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Pension Benefits
Assumptions Used to Determine Benefit Obligation
Discount rate	4.12%	4.99%
Initial cash balance crediting rate assumed for the next year	2.75%	3.90%
Rate to which the cash balance crediting rate is assumed to increase (the ultimate rate)	3.50%	4.70%
Year that the cash balance crediting rate reaches the ultimate rate	2020	2019
Rate of compensation increase	3.00%	3.00%
Assumptions Used to Determine Benefit Cost
Discount rate	4.99%	4.12%
Initial cash balance crediting rate assumed for the next year	3.90%	3.00%
Rate to which the cash balance crediting rate is assumed to increase (the ultimate rate)	4.70%	4.25%
Year that the cash balance crediting rate reaches the ultimate rate	2019	2018
Expected long-term return on plan assets	8.00%	8.00%
Rate of compensation increase	3.00%	2.75%
Medical and Life Benefits
Assumptions Used to Determine Benefit Obligation
Discount rate	4.04%	4.90%
Assumptions Used to Determine Benefit Cost
Discount rate	4.90%	4.02%
Expected long-term return on plan assets	7.45%	7.33%
Benefit Obligation
Defined Benefit Plan Disclosure (Table Amounts)
Initial health care cost trend rate assumed for the next year	6.50%	6.50%
Rate to which the health care cost trend rate is assumed to decline (the ultimate trend rate)	5.00%	5.00%
Year that the health care cost trend rate reaches the ultimate trend rate	2019	2017
Post-retirement Benefit Cost
Defined Benefit Plan Disclosure (Table Amounts)
Initial health care cost trend rate assumed for the next year	6.50%	7.00%
Rate to which the health care cost trend rate is assumed to decline (the ultimate trend rate)	5.00%	5.00%
Year that the health care cost trend rate reaches the ultimate trend rate	2017	2017

Cash Balance Crediting Rate Assumed for next fiscal year used to calculate benefit cost

No definition available.

Name:	noc_DefinedBenefitPlanBenefitCostCashBalanceCreditingRateAssumedfornextfiscalyear
Namespace Prefix:	noc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Defined Benefit Plan, Cash Balance Crediting Rate, Year that the rate reaches the ultimate rate, used to calculate benefit cost.

+ References

No definition available.

+ Details

Name:	noc_DefinedBenefitPlanBenefitCostCashBalanceCreditingRateYearthattheratereachestheultimaterate
Namespace Prefix:	noc_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Defined Benefit Plan Ultimate Cash Balance Crediting Rate, used to calculate benefit cost

+ References

No definition available.

+ Details

Name:	noc_DefinedBenefitPlanBenefitCostUltimateCashBalanceCreditingRate
Namespace Prefix:	noc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Cash Balance Crediting Rate Assumed for Next Fiscal Year used to calculate the benefit obligation.

+ References

No definition available.

+ Details

Name:	noc_DefinedBenefitPlanBenefitObligationCashBalanceCreditingRateAssumedforNextFiscalYear
Namespace Prefix:	noc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Defined Benefit Plan, Cash Balance Crediting Rate, Year that rate reaches ultimate rate, used to calculate benefit obligation, in CCYY format.

+ References

No definition available.

+ Details

Name:	noc_DefinedBenefitPlanBenefitObligationCashBalanceCreditingRateYearthatratereachesultimaterate
Namespace Prefix:	noc_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Defined Benefit Plan Ultimate Cash Balance Crediting Rate used to calculate the benefit obligation

+ References

No definition available.

+ Details

Name:	noc_DefinedBenefitPlanBenefitObligationUltimateCashBalanceCreditingRate
Namespace Prefix:	noc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The interest rate used to adjust for the time value of money for the plan.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Expected rate of compensation increases (for pay-related plans).

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The interest rate used to adjust for the time value of money.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 30

-Glossary Expected Long-Term Rate of Return on Plan Assets

-URI http://asc.fasb.org/extlink&oid=6512013

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (k)(3)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Expected rate of compensation increases (for pay-related plans).

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (l)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Health Care Cost Trend Rate

-URI http://asc.fasb.org/extlink&oid=6514820

+ Details

Name:	us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The ultimate trend rate for health care costs.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Year the ultimate health care cost trend rate is expected to be reached, in CCYY format.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanYearThatRateReachesUltimateTrendRate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=noc_BenefitObligationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=noc_PostretirementBenefitCostMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: