XML 46 R45.htm IDEA: XBRL DOCUMENT v2.4.0.8

Income Tax - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 28, 2014
Income Tax Disclosure [Abstract]
Possible chance of tax position sustained, percentage	50.00%
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	$ 0

X

- Definition

Possible chance of tax position sustainable, percentage.

+ References

No definition available.

+ Details

Name:	gd_PossibleChanceOfTaxPositionSustainablePercentage
Namespace Prefix:	gd_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

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

X

- Definition

The amount of the unrecognized tax benefit of a position taken for which it is reasonably possible that the total amount thereof will significantly increase or decrease within twelve months of the balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

+ Details

Name:	us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant