Fair Value - Level 3 Valuation Inputs (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities:	$ 438	$ 469
Net derivatives	183	151
Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	76,992	78,728
Available-for-sale securities:	438	469
Significant Unobservable Inputs (Level 3)
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	25	28
Available-for-sale securities:	399	427
Significant Unobservable Inputs (Level 3) \| Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	25	28
Available-for-sale securities:	399	427
Significant Unobservable Inputs (Level 3) \| Recurring \| Dealer Mark and Discounted Cash Flow
Fair Value Inputs, Quantitative Information [Line Items]
Net derivatives	33	39
Mortgage-related securities \| Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	1,185	1,098
Mortgage-related securities \| Significant Unobservable Inputs (Level 3) \| Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	25	28
Mortgage-related securities \| Significant Unobservable Inputs (Level 3) \| Recurring \| Primarily Consensus
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	25	28
Agency \| Significant Unobservable Inputs (Level 3) \| Recurring \| Consensus
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities:	289
Agency \| Significant Unobservable Inputs (Level 3) \| Recurring \| Consensus
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities:		301
Other mortgage-related \| Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities:	114	130
Other mortgage-related \| Significant Unobservable Inputs (Level 3) \| Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities:	110	126
Other mortgage-related \| Significant Unobservable Inputs (Level 3) \| Recurring \| Primarily Discounted Cash Flow, Single Vendor, and Consensus
Fair Value Inputs, Quantitative Information [Line Items]
Available-for-sale securities:	$ 110	$ 126

Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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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.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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