Contingent Liabilities and Guarantees - Narrative (Details) $ in Millions	3 Months Ended
Mar. 31, 2023 USD ($)
Standby letters of credit
Commitments Contingencies And Guarantees [Line Items]
Remaining weighted-average life of standby letters of credit (in years)	1 year 6 months
Recourse agreement with FNMA
Commitments Contingencies And Guarantees [Line Items]
Weighted-average remaining term for outstanding commercial mortgage loans (in years)	7 years 3 months 18 days
Unpaid principal balance outstanding of loans sold	$ 22,200
Maximum potential amount of undiscounted future payments possibly required as percentage of principal balance of loans outstanding (as a percent)	30.70%
Residential mortgage reserve
Commitments Contingencies And Guarantees [Line Items]
Unpaid principal balance outstanding of loans sold	$ 10,900
Maximum potential amount of undiscounted future payments possibly required as percentage of principal balance of loans outstanding (as a percent)	30.00%
Liability for estimated repurchase obligations on loans sold	$ 13
Written Put Options, Guarantees
Commitments Contingencies And Guarantees [Line Items]
Weighted average life of written put options (in years)	2 years
Minimum \| Standby letters of credit
Commitments Contingencies And Guarantees [Line Items]
Remaining actual life of standby letters of credit (in years)	1 year
Minimum \| Low
Commitments Contingencies And Guarantees [Line Items]
Guarantee obligations (as a percent)	0.00%
Minimum \| Moderate
Commitments Contingencies And Guarantees [Line Items]
Guarantee obligations (as a percent)	30.00%
Minimum \| High
Commitments Contingencies And Guarantees [Line Items]
Guarantee obligations (as a percent)	70.00%
Maximum \| Standby letters of credit
Commitments Contingencies And Guarantees [Line Items]
Remaining actual life of standby letters of credit (in years)	11 years 8 months 12 days
Maximum \| Low
Commitments Contingencies And Guarantees [Line Items]
Guarantee obligations (as a percent)	30.00%
Maximum \| Moderate
Commitments Contingencies And Guarantees [Line Items]
Guarantee obligations (as a percent)	70.00%

Commitments Contingencies And Guarantees [Line Items]

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- Definition

Guarantor Obligations, Maximum Exposure, Undiscounted as Percentage of Total Loans Outstanding

+ References

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- Definition

Remaining actual life letters of credit.

+ References

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Remaining weighted-average life of standby letters of credit.

+ References

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- Definition

Weighted average life of written put options.

+ References

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- Definition

Weighted-average remaining term for outstanding commercial mortgage loans.

+ References

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- Definition

Amount to be repaid to the counterparty to the repurchase agreement when the carrying amount (or market value, if higher than the carrying amount) of securities or other assets sold under the repurchase agreement exceeds 10 percent of total assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(m)(1)(i))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(m)(1)(ii)(A)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

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- Definition

Indicates, if estimable, (as a percentage) the approximate extent to which the proceeds from liquidation of any assets held either as collateral or by third parties would be expected to cover the maximum potential amount of future payments under the guarantee or each group of similar guarantees.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482425/460-10-50-4

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- Definition

Amount of the recorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 440
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482648/440-10-50-6

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