Investment Securities - Additional Information (Detail)	3 Months Ended
Mar. 31, 2023 USD ($) Security	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)
Investment Holdings [Line Items]
Gross realized gains(loss) on sale of investment securities	$ 0	$ 0
Number of debt securities with aggregate gross unrealized losses \| Security	4,132
Unrealized losses on individual debt securities	$ (1,400,000,000)
Cost method equity securities	907,000,000
Investment securities pledged to secure debt carrying value	9,000,000,000.0		$ 7,900,000,000
Carrying value of investment securities pledged related to repurchase transactions	1,200,000,000		567,000,000
Available-for-Sale Securities [Member]
Investment Holdings [Line Items]
Allowance for credit losses	$ 0		$ 0

Carrying value of investment securities pledged.

No definition available.

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- Definition

Carrying value of investment securities pledged related to repurchase transactions..

+ References

No definition available.

+ Details

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- Definition

Number of debt securities with gross losses.

+ References

No definition available.

+ Details

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- Definition

Amount of realized gain (loss) on investment in debt and equity securities.

+ References

No definition available.

+ Details

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- Definition

Amount of allowance for credit loss for debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aaa)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (f)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

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- Definition

Amount of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in net income (trading).

+ References

No definition available.

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- Definition

Cost of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Excludes equity method investment and investment in equity security without readily determinable fair value.

+ 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

No definition available.

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