Advances Redemption Terms (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Advances by Redemption Terms [Line Items]
Deposit Liabilities Reclassified as Loans Receivable	$ 3,293	$ 576
Weighted Average Interest Rate on Overdrawn Demand Deposit	3.85%	3.72%
Federal Home Loan Bank, Advances, Maturities Summary, in Next Rolling Twelve Months	$ 30,529,331	$ 22,406,895
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Next Twelve Rolling Months	3.73%	3.95%
Federal Home Loan Bank, Advances, Maturities Summary, in Rolling Year Two	$ 7,942,718	$ 15,634,197
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Rolling Year Two	3.92%	3.63%
Federal Home Loan Bank, Advances, Maturities Summary, in Rolling Year Three	$ 2,281,168	$ 6,251,402
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Rolling Year Three	4.06%	4.10%
Federal Home Loan Bank, Advances, Maturities Summary, in Rolling Year Four	$ 1,369,738	$ 1,514,170
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Rolling Year Four	3.89%	4.17%
Federal Home Loan Bank, Advances, Maturities Summary, in Rolling Year Five	$ 1,531,207	$ 1,182,382
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Rolling Year Five	3.75%	3.92%
Federal Home Loan Bank, Advances, Maturities Summary in Rolling Year Six Through Rolling Year Fifteen	$ 3,893,152	$ 3,837,323
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Rolling Year Six Through Rolling Year Fifteen	3.41%	3.27%
Federal Home Loan Bank, Advances, Maturities Summary, after Rolling Year Fifteen	$ 10,333	$ 13,320
Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing after Rolling Year Fifteen	3.50%	3.47%
Federal Home Loan Bank Advances Par Value	$ 47,560,940	$ 50,840,265
Federal Home Loan Bank, Advances, Weighted Average Interest Rate	3.75%	3.83%
Deferred Prepayment Fees	$ (2,880)	$ (2,329)
Federal Home Loan Bank Advances, Valuation Adjustments For Hedging Activities	(147,069)	(17,830)
Federal Home Loan Bank Advances	$ 47,410,991	$ 50,820,106

[Line Items] for Advances by Redemption Terms

No definition available.

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

- Definition

Deferred Prepayment Fees on Advances

+ References

No definition available.

+ Details

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

- Definition

Federal Home Loan Bank, Advances, Maturities Summary, after Rolling Year Fifteen

+ References

No definition available.

+ Details

Name:	fhlbd_FederalHomeLoanBankAdvancesMaturitiesSummaryAfterRollingYearFifteen
Namespace Prefix:	fhlbd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Federal Home Loan Bank, Advances, Maturities Summary in Rolling Year Six Through Rolling Year Fifteen

+ References

No definition available.

+ Details

Name:	fhlbd_FederalHomeLoanBankAdvancesMaturitiesSummaryInRollingYearSixThroughRollingYearFifteen
Namespace Prefix:	fhlbd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing after Rolling Year Fifteen

+ References

No definition available.

+ Details

Name:	fhlbd_FederalHomeLoanBankAdvancesWeightedAverageInterestRateMaturingAfterRollingYearFifteen
Namespace Prefix:	fhlbd_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Federal Home Loan Bank, Advances, Weighted Average Interest Rate, Maturing in Rolling Year Six Through Rolling Year Fifteen

+ References

No definition available.

+ Details

Name:	fhlbd_FederalHomeLoanBankAdvancesWeightedAverageInterestRateMaturingInRollingYearSixThroughRollingYearFifteen
Namespace Prefix:	fhlbd_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of deposits held by the entity that have been reclassified as loan balances receivable, for example, but not limited to, overdrafts receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-SubTopic 405
-Topic 942
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478353/942-405-50-1

+ Details

Name:	us-gaap_DepositLiabilitiesReclassifiedAsLoansReceivable1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of Federal Home Loan Bank (FHLBank) advances to member financial institutions.

+ References

No definition available.

+ Details

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

- Definition

Par amount of advances made and reported by Federal Home Loan Bank (FHLBank) 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

No definition available.

+ Details

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

- Definition

Par amount of advances made and reported by Federal Home Loan Bank (FHLBank) 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

No definition available.

+ Details

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

- Definition

Par amount of advances made and reported by Federal Home Loan Bank (FHLBank) 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

No definition available.

+ Details

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

- Definition

Par amount of advances made and reported by Federal Home Loan Bank (FHLBank) 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

No definition available.

+ Details

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

- Definition

Par amount of advances made and reported by Federal Home Loan Bank (FHLBank) 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

No definition available.

+ Details

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

- Definition

Par amount of advances made and reported by Federal Home Loan Bank (FHLBank).

+ References

No definition available.

+ Details

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

- Definition

Amount of accumulated increase (decrease) on advances made and reported by Federal Home Loan Bank (FHLBank) from hedging adjustments.

+ References

No definition available.

+ Details

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

- Definition

Weighted average interest rate on advances made and reported by Federal Home Loan Bank (FHLBank).

+ References

No definition available.

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average interest rate on advances made and reported by Federal Home Loan Bank (FHLBank) 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

No definition available.

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesWeightedAverageInterestRateMaturingInNextTwelveRollingMonths
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average interest rate on advances made and reported by Federal Home Loan Bank (FHLBank) 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

No definition available.

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesWeightedAverageInterestRateMaturingInRollingYearFive
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average interest rate on advances made and reported by Federal Home Loan Bank (FHLBank) 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

No definition available.

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesWeightedAverageInterestRateMaturingInRollingYearFour
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average interest rate on advances made and reported by Federal Home Loan Bank 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

No definition available.

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesWeightedAverageInterestRateMaturingInRollingYearThree
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average interest rate on advances made and reported by Federal Home Loan Bank (FHLBank) 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

No definition available.

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesWeightedAverageInterestRateMaturingInRollingYearTwo
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average interest rate on overdrawn demand deposit.

+ References

No definition available.

+ Details

Name:	us-gaap_WeightedAverageInterestRateOnOverdrawnDemandDeposit
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant