Investment Securities Investment Securities (Summary of Investment in Agency Security) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	$ 44,880	$ 53,628
Debt Securities, Trading and Available-for-sale	40,904	54,421
Total agency MBS, at fair value	39,490	52,604
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	111	325
Debt Securities, Trading and Available-for-sale	90	329
Commercial Mortgage Backed Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	605	505
Debt Securities, Trading and Available-for-sale	567	514
Credit Risk Transfer Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	779	955
Debt Securities, Trading and Available-for-sale	757	974
Fixed Income Securities [Member] \| Agency Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	43,046	51,546
Debt Securities, Trading and Available-for-sale	39,169	52,289
Adjustable-Rate [Member] \| Agency Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	126	45
Debt Securities, Trading and Available-for-sale	122	47
Collateralized Mortgage Obligations [Member] \| Agency Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	136	182
Debt Securities, Trading and Available-for-sale	129	188
Interest Only And Principal Only Strip [Member] \| Agency Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	77	70
Debt Securities, Trading and Available-for-sale	70	80
Agency Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	$ 43,385	$ 51,843

Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) at cost.

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- Definition

Represents total investment in agency securities at fair value.

+ References

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- Definition

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124260329&loc=d3e26610-111562

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+ References

No definition available.

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