Fair Value - Level 3 Valuation Inputs (Details) $ in Millions	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	$ 584	$ 696
Derivatives	104	172
Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	51,288	50,129
Total Fair Value	584	696
Significant Unobservable Inputs (Level 3)
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	24	47
Total Fair Value	415	634
Significant Unobservable Inputs (Level 3) \| Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	24	47
Total Fair Value	415	634
Derivatives	39	(37)
Significant Unobservable Inputs (Level 3) \| Recurring \| Discounted Cash Flow
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	31	(62)
Significant Unobservable Inputs (Level 3) \| Recurring \| Dealer Mark
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	8	25
Mortgage-related \| Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	2,634	3,211
Mortgage-related \| Significant Unobservable Inputs (Level 3) \| Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	24	47
Mortgage-related \| Significant Unobservable Inputs (Level 3) \| Recurring \| Various
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	24	47
Agency \| Significant Unobservable Inputs (Level 3) \| Recurring \| Consensus
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	212	371
Other mortgage-related \| Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	208	270
Other mortgage-related \| Significant Unobservable Inputs (Level 3) \| Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	203	263
Other mortgage-related \| Significant Unobservable Inputs (Level 3) \| Recurring \| Various
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	96	25
Other mortgage-related \| Significant Unobservable Inputs (Level 3) \| Recurring \| Discounted Cash Flow
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	$ 91	$ 142
Other mortgage-related \| Significant Unobservable Inputs (Level 3) \| Recurring \| Discounted Cash Flow \| Minimum \| Default Rate
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (percent)	0.04880	0.05310
Other mortgage-related \| Significant Unobservable Inputs (Level 3) \| Recurring \| Discounted Cash Flow \| Maximum \| Default Rate
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (percent)	0.05180	0.05820
Other mortgage-related \| Significant Unobservable Inputs (Level 3) \| Recurring \| Discounted Cash Flow \| Weighted Average \| Default Rate
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (percent)	0.05036	0.05577
Other mortgage-related \| Significant Unobservable Inputs (Level 3) \| Recurring \| Single Vendor
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	$ 16	$ 96

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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