Unbilled Receivables (Narrative) (Details) $ in Millions	Dec. 31, 2021 USD ($) contract	Dec. 31, 2020 USD ($) contract
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivable	$ 39,566	$ 36,657
Unbilled receivables	8,498	8,024
G&A costs in unbilled revenue	501	427
Combat Systems \| International Customer Through Canadian Government
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivable	3,300	$ 3,400
Combat Systems \| Large International Wheel Armored Vehicle Customer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	2,000
Combat Systems \| Tracked Vehicle Customer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unbilled receivables	$ 1,300
Combat Systems \| Large International Customer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number Of Contracts \| contract	2	2

Number Of Contracts

No definition available.

Name:	gd_NumberOfContracts
Namespace Prefix:	gd_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

The actual or estimated amount of general and administrative expense remaining in inventory as of the balance sheet date.

+ References

+ Details

Name:	us-gaap_InventoryForLongTermContractsOrProgramsGeneralAndAdministrativeCostsIncludedInInventory
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.3(c)(3))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 912
-SubTopic 310
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=123371682&loc=d3e55302-109406

+ Details

Name:	us-gaap_UnbilledContractsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount received for services rendered and products shipped, but not yet billed, for non-contractual agreements due within one year or the normal operating cycle, if longer.

+ References

No definition available.

+ Details

Name:	us-gaap_UnbilledReceivablesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=gd_CombatSystemsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=gd_InternationalCustomerThroughCanadianGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=gd_LargeInternationalWheelArmoredVehicleCustomerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=gd_TrackedVehicleCustomerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=gd_LargeInternationalCustomerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: