Income Taxes (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Unrecognized Tax Benefits Rollforward (Table Amounts) [Abstract]
Unrecognized tax benefits at beginning of the year	$ 241us-gaap_UnrecognizedTaxBenefits	$ 156us-gaap_UnrecognizedTaxBenefits	$ 118us-gaap_UnrecognizedTaxBenefits
Additions based on tax positions related to the current year	62	56	12
Additions for tax positions of prior years	9	44	28
Settlements with taxing authorities	(61)	(1)	(1)
Other, net	(41)noc_UnrecognizedTaxBenefitsOther	(14)noc_UnrecognizedTaxBenefitsOther	(1)noc_UnrecognizedTaxBenefitsOther
Net change in unrecognized tax benefits	(31)	85	38
Unrecognized tax benefits at end of the year	$ 210us-gaap_UnrecognizedTaxBenefits	$ 241us-gaap_UnrecognizedTaxBenefits	$ 156us-gaap_UnrecognizedTaxBenefits

Unrecognized Tax Benefits, Other

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Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Unrecognized Tax Benefit

-URI http://asc.fasb.org/extlink&oid=6527854

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-Publisher FASB

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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The net amount of all increases and decreases in unrecognized tax benefits for the period.

+ References

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-Name Accounting Standards Codification

-Topic 740

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