Name:	fhlbdm_AHPSupplementalVoluntaryContributionExpense
Namespace Prefix:	fhlbdm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

[Line Items] for Affordable Housing Program [Table]

No definition available.

Name:	fhlbdm_AffordableHousingProgramLineItems
Namespace Prefix:	fhlbdm_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Commitment by the FHLB to contribute towards other housing and community investment activities above the required statutory contributions

No definition available.

Name:	fhlbdm_VoluntaryAffordableHousingProgramExpense
Namespace Prefix:	fhlbdm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Amount of expense for Affordable Housing Program (AHP) assessments required by the Federal Home Loan Bank Act of 1932.

No definition available.

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

Amount of obligation related to Affordable Housing Program (AHP) assessments required by the Federal Home Loan Bank Act of 1932.

No definition available.

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

Amount of cash outflow for payments made by the Federal Home Loan Banks (FHLBanks) to the Affordable Housing Program (AHP).

No definition available.