Consolidated Obligations Contractual Maturity or Next Call Date (Details) - Unsecured Debt [Member] - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Consolidated Obligations by Contractual Maturity or Next Call Date [Line Items]
Debt, Gross	$ 56,385,845	$ 58,340,975
Earlier of Contractual Maturity or Next Call Date [Member]
Consolidated Obligations by Contractual Maturity or Next Call Date [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Rolling Twelve Months	51,271,520	52,120,085
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Two	2,386,820	3,773,330
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Three	1,632,005	1,464,430
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Four	795,500	777,130
Long-term Debt, Maturities, Repayments of Principal in Rolling Year Five	285,000	161,000
Long-term Debt, Maturities, Repayments of Principal in Rolling after Year Five	15,000	45,000
Debt, Gross	$ 56,385,845	$ 58,340,975

[Line Items] for Consolidated Obligations by Contractual Maturity or Next Call Date [Table]

No definition available.

Name:	fhlbd_ConsolidatedObligationsbyContractualMaturityorNextCallDateLineItems
Namespace Prefix:	fhlbd_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Including current and noncurrent portions, aggregate carrying principal amount of borrowings as of the balance sheet date before deducting unamortized discount or premiums (if any).

+ References

No definition available.

+ Details

Name:	fhlbd_DebtGross
Namespace Prefix:	fhlbd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477314/942-235-S99-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-4

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second rolling twelve months following the latest balance sheet. For interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fhlbd_LongTermDebtByMaturityTypeAxis=fhlbd_EarlierOfContractualMaturityOrNextCallDateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: