Commitment and Contingencies - Product Warranties (Details) $ in Millions	9 Months Ended
Sep. 30, 2021 USD ($)
Movement in Standard Product Warranty Accrual [Roll Forward]
Beginning balance	$ 17
Additional provision	12
Reversal and utilization	(11)
Ending balance	$ 18
Minimum
Product Warranty Liability [Line Items]
Product warranty term	1 year
Maximum
Product Warranty Liability [Line Items]
Product warranty term	3 years

Standard Product Warrant Accrual, Decrease For Payments And (Increase) Decrease For Preexisting Warranties

No definition available.

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Namespace Prefix:	drs_
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Balance Type:	debit
Period Type:	duration

- Definition

Standard Product Warranty, Term

+ References

No definition available.

+ Details

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Namespace Prefix:	drs_
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

Amount as of the balance sheet date of the aggregate standard product warranty liability. Does not include the balance for the extended product warranty liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)(1),(c)(5)
-URI http://asc.fasb.org/extlink&oid=123368208&loc=d3e12565-110249

+ Details

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

- Definition

Amount of increase in the standard product warranty accrual from warranties issued. Excludes extended product warranties.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph ((c)(3))
-URI http://asc.fasb.org/extlink&oid=123368208&loc=d3e12565-110249

+ Details

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Period Type:	duration

- Details

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