Fair Value - Level 3 Valuation Inputs (Details) $ in Millions	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	$ 679	$ 696
Derivatives	150	172
Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	50,410	50,129
Total Fair Value	679	696
Significant Unobservable Inputs (Level 3)
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	32	47
Total Fair Value	622	634
Significant Unobservable Inputs (Level 3) | Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	32	47
Total Fair Value	622	634
Derivatives	(38)	(37)
Significant Unobservable Inputs (Level 3) | Recurring | Discounted Cash Flow
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	(63)	(62)
Significant Unobservable Inputs (Level 3) | Recurring | Dealer Mark
Fair Value Inputs, Quantitative Information [Line Items]
Derivatives	25	25
Mortgage-related | Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	2,852	3,211
Mortgage-related | Significant Unobservable Inputs (Level 3) | Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	32	47
Mortgage-related | Significant Unobservable Inputs (Level 3) | Recurring | Various
Fair Value Inputs, Quantitative Information [Line Items]
Trading securities	32	47
Agency | Significant Unobservable Inputs (Level 3) | Recurring | Consensus
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	362	371
Other mortgage-related | Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	265	270
Other mortgage-related | Significant Unobservable Inputs (Level 3) | Recurring
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	260	263
Other mortgage-related | Significant Unobservable Inputs (Level 3) | Recurring | Various
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	25	25
Other mortgage-related | Significant Unobservable Inputs (Level 3) | Recurring | Discounted Cash Flow
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	$ 138	$ 142
Other mortgage-related | Significant Unobservable Inputs (Level 3) | Recurring | Discounted Cash Flow | Total available-for-sale securities | Minimum | Default Rate
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (percent)	0.05300	0.05310
Other mortgage-related | Significant Unobservable Inputs (Level 3) | Recurring | Discounted Cash Flow | Total available-for-sale securities | Maximum | Default Rate
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (percent)	0.05600	0.05820
Other mortgage-related | Significant Unobservable Inputs (Level 3) | Recurring | Discounted Cash Flow | Total available-for-sale securities | Weighted Average | Default Rate
Fair Value Inputs, Quantitative Information [Line Items]
Spreads (percent)	0.05455	0.05577
Other mortgage-related | Significant Unobservable Inputs (Level 3) | Recurring | Single Vendor
Fair Value Inputs, Quantitative Information [Line Items]
Total Fair Value	$ 97	$ 96