Commitments and Contingencies - Additional Information (Detail) $ in Millions	9 Months Ended
Sep. 30, 2016 USD ($)
Commitments and Contingencies Disclosure [Line Items]
Self insured retention	$ 25
Commitment to fund limited partnership investments	188
Commitment to fund U.S. commercial mortgage loan investments	106
Commitment to fund private placement investments	43
Long-term Care Insurance Class Action Lawsuit
Commitments and Contingencies Disclosure [Line Items]
Settlement payment	(219)
Long-term Care Insurance Class Action Lawsuit \| Insurance Carriers
Commitments and Contingencies Disclosure [Line Items]
Settlement payment	(150)
Long-term Care Insurance Class Action Lawsuit \| Genworth Financial, Inc.
Commitments and Contingencies Disclosure [Line Items]
Settlement payment	(69)
Legal fees	10
Settlement payment and legal fees incurred	$ 79

Amount incurred or accrued for the self insured retention of executive and organization liability program.

No definition available.

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Namespace Prefix:	gnw_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of commitment to fund limited partnership investments as of the balance sheet date that is not recorded.

+ References

No definition available.

+ Details

Name:	gnw_CommitmentToFundLimitedPartnershipInvestments
Namespace Prefix:	gnw_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of commitment to fund private placement investments as of the balance sheet date that is not recorded.

+ References

No definition available.

+ Details

Name:	gnw_CommitmentToFundPrivatePlacementInvestments
Namespace Prefix:	gnw_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of commitment to fund U.S. commercial mortgage loan investments as of the balance sheet date that is not recorded.

+ References

No definition available.

+ Details

Name:	gnw_CommitmentToFundUSCommercialMortgageLoanInvestments
Namespace Prefix:	gnw_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Commitments and Contingencies Disclosure [Line Items]

+ References

No definition available.

+ Details

Name:	gnw_CommitmentsAndContingenciesDisclosureLineItems
Namespace Prefix:	gnw_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The total of amount of judgment or settlement awarded to (against) the entity in respect of litigation and the amount of expense provided in the period for legal costs incurred on or before the balance sheet date pertaining to resolved, pending or threatened litigation, including arbitration and mediation proceedings.

+ References

No definition available.

+ Details

Name:	gnw_SettlementAmountAndLegalFeesIncurred
Namespace Prefix:	gnw_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of expense provided in the period for legal costs incurred on or before the balance sheet date pertaining to resolved, pending or threatened litigation, including arbitration and mediation proceedings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

Name:	us-gaap_LegalFees
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of judgment or settlement awarded to (against) the entity in respect of litigation.

+ References

No definition available.

+ Details

Name:	us-gaap_LitigationSettlementAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_LitigationCaseAxis=gnw_LongTermCareInsuranceClassActionLawsuitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=gnw_InsuranceCarriersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=gnw_GenworthFinancialIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: