Derivatives and Hedging Activities - Cumulative Basis Adjustments on Fair Value Hedges (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Fair Value	$ 42,437	$ 45,364
Long-term debt \| Interest rate
Derivatives, Fair Value [Line Items]
Carrying amount of hedged item	8,770	7,553
Hedge accounting basis adjustment	(230)	138
Long-term debt \| Interest rate \| Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Hedge accounting basis adjustment	(7)	(7)
Securities available for sale \| Interest rate
Derivatives, Fair Value [Line Items]
Carrying amount of hedged item	405	6,280
Hedge accounting basis adjustment	37	134
Fair Value	$ 732,000	$ 7,700

Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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+ References

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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/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4EE
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL109999712-113959

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- Definition

Amount of liability hedged in fair value hedging relationship.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4EE
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL109999712-113959

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