Derivative Instruments and Hedging Activities - Hedged Items in Fair Value Hedging Relationship (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Hedged Items In Fair Value Hedging Relationship [Line Items]
Hedged Assets, Fair Value Hedge, Cumulative Increase (Decrease)	$ (10)	$ (13)
Hedged Assets, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)	870	236
Prepayable Financial Asset Closed Portfolio, Last-of-Layer, Amortized Cost	655	225
Available-for-sale securities
Hedged Items In Fair Value Hedging Relationship [Line Items]
Carrying Amount of Assets	4,608	3,983
Hedged Assets, Fair Value Hedge, Cumulative Increase (Decrease)	(102)	(80)
Hedged Assets, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)	144	200
Interest-bearing deposits
Hedged Items In Fair Value Hedging Relationship [Line Items]
Carrying Amount Of Liabilities	(17,225)	(17,280)
Hedged Liabilities, Fair Value Hedge, Cumulative Increase (Decrease)	580	500
Hedged Liabilities, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)	(1)	(1)
Securitized debt obligations
Hedged Items In Fair Value Hedging Relationship [Line Items]
Carrying Amount Of Liabilities	(13,117)	(11,921)
Hedged Liabilities, Fair Value Hedge, Cumulative Increase (Decrease)	757	748
Hedged Liabilities, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)	0	0
Senior and subordinated notes
Hedged Items In Fair Value Hedging Relationship [Line Items]
Carrying Amount Of Liabilities	(30,035)	(24,544)
Hedged Liabilities, Fair Value Hedge, Cumulative Increase (Decrease)	1,931	1,542
Hedged Liabilities, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)	$ (413)	$ (527)

Carry amount of assets hedged in fair value hedging relationship

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- Definition

The carry amount of liabilities in fair value hedging relationship

+ References

No definition available.

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- Definition

[Line Items] for Table shows the carrying amount and associated cumulative basis adjustment related to the application of hedge accounting that is included in the carrying amount of hedged assets and liabilities in fair value hedging relationships.

+ References

No definition available.

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- Definition

Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk, remaining after discontinued hedge.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 181
-Subparagraph (b)
-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 4EE
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4EE

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- Definition

Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 181
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480401/815-10-55-181

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4EE
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4EE

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- Definition

Amount of cumulative increase (decrease) in fair value of hedged liability in fair value hedge, attributable to hedged risk, remaining after discontinued hedge.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4EE
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4EE

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- Definition

Amount of cumulative increase (decrease) in fair value of hedged liability in fair value hedge, attributable to hedged risk.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4EE
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4EE

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- Definition

Amortized cost of closed portfolio of financial asset used to designate hedging relationship in which hedged item is expected to be outstanding for designated hedged period.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 181
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480401/815-10-55-181

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-Topic 815
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-Paragraph 4EEE
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4EEE

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