Fair Value Option - Summary of Fair Value and Unpaid Principal Balance (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Option, Quantitative Disclosures [Line Items]
Client share repurchase asset, Fair Value	$ 661	$ 10
Client shares repurchase liability, Fair Value	661	10
Student loans held for investment
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans, designated under fair value option	14	15
Loans held for investment, Unpaid Principal Balance	16	17
Fair Value Over (Under) Unpaid Principal Balance	(2)	(2)
Commercial loans held for sale
Fair Value, Option, Quantitative Disclosures [Line Items]
Commercial loans held for sale, Fair Value	264	250
Commercial loans held for sale, Unpaid Principal Balance	272	256
Fair Value Over (Under) Unpaid Principal Balance	(8)	(6)
Client share repurchase asset
Fair Value, Option, Quantitative Disclosures [Line Items]
Client share repurchase asset, Fair Value	661	10
Client share repurchase asset, Unpaid Principal Balance	661	10
Fair Value Over (Under) Unpaid Principal Balance	0	0
Fixed rate long-term debt
Fair Value, Option, Quantitative Disclosures [Line Items]
Fixed rate long-term debt, Fair Value	756	749
Fixed rate long-term debt, Unpaid Principal Balance	741	741
Fair Value Over (Under) Unpaid Principal Balance	15	8
Fixed rate long-term debt \| Structured notes
Fair Value, Option, Quantitative Disclosures [Line Items]
Hybrid instruments, structured notes, Fair Value	6,114	6,790
Hybrid instruments, Unpaid Principal Balance	5,741	6,418
Fair Value Over (Under) Unpaid Principal Balance	373	372
Structured deposits
Fair Value, Option, Quantitative Disclosures [Line Items]
Hybrid instruments, structured deposits, Fair Value	2,084	1,821
Hybrid instruments, Unpaid Principal Balance	2,057	1,816
Fair Value Over (Under) Unpaid Principal Balance	27	5
Client share repurchase liability
Fair Value, Option, Quantitative Disclosures [Line Items]
Client shares repurchase liability, Fair Value	661	10
Unpaid Principal Balance, Other Liabilities, Fair Value Disclosure	661	10
Fair Value Over (Under) Unpaid Principal Balance	$ 0	$ 0

Fair Value, Option, Loans Held As Assets

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- Definition

Fair Value Over (Under) Unpaid Principal Balance

+ References

No definition available.

+ Details

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- Definition

Fixed-rate debt accounted for under fair value option.

+ References

No definition available.

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- Definition

Unpaid Principal Balance Commercial Syndicated Loans Held For Sale Carried At Fair Value

+ References

No definition available.

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- Definition

Unpaid Principal Balance, Loans Receivable

+ References

No definition available.

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- Definition

Unpaid principal balance on fixed-rate debt accounted for under FVO.

+ References

No definition available.

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- Definition

Unpaid Principal Balance On Hybrid Instruments At Fair Value Option

+ References

No definition available.

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- Definition

Unpaid Principal Balance, Other Assets, Fair Value Disclosure

+ References

No definition available.

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- Definition

Unpaid Principal Balance, Other Liabilities, Fair Value Disclosure

+ References

No definition available.

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- Definition

Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

+ References

No definition available.

+ Details

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-30

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-31

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-32

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- Definition

Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

+ References

No definition available.

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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- Definition

Fair value portion of other assets.

+ References

No definition available.

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- Definition

Fair value portion of other liabilities.

+ References

No definition available.

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