Fair Value Option - Summary of Fair Value and Unpaid Principal Balance (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Option, Quantitative Disclosures [Line Items]
Commercial loans held for sale, Fair Value	$ 144	$ 48
Student loans held for sale
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans, designated under fair value option	24	25
Loans held for investment, Unpaid Principal Balance	26	28
Fair Value Over (Under) Unpaid Principal Balance	(2)	(3)
Commercial loans held for sale
Fair Value, Option, Quantitative Disclosures [Line Items]
Commercial loans held for sale, Fair Value	120	23
Commercial loans held for sale, Unpaid Principal Balance	126	23
Fair Value Over (Under) Unpaid Principal Balance	(6)	0
Fixed rate long-term debt
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value Over (Under) Unpaid Principal Balance	104	204
Fixed rate long-term debt, Fair Value	845	945
Fixed rate long-term debt, Unpaid Principal Balance	741	741
Fixed rate long-term debt \| Structured notes
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value Over (Under) Unpaid Principal Balance	570	1,163
Hybrid instruments, Unpaid Principal Balance	6,250	6,834
Hybrid instruments, structured notes, Fair Value	6,820	7,997
Structured deposits
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value Over (Under) Unpaid Principal Balance	189	284
Hybrid instruments, structured deposits, Fair Value	2,379	2,749
Hybrid instruments, Unpaid Principal Balance	$ 2,190	$ 2,465

Fair Value, Option, Loans Held As Assets

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- Definition

Fair Value Over (Under) Unpaid Principal Balance

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No definition available.

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- Definition

Fixed-rate debt accounted for under fair value option.

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No definition available.

+ Details

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- Definition

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

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No definition available.

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- Definition

Unpaid Principal Balance, Loans Receivable

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No definition available.

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- Definition

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

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No definition available.

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- Definition

Unpaid Principal Balance On Hybrid Instruments At Fair Value Option

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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.

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No definition available.

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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.

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- Definition

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

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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.

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No definition available.

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