Derivatives - Derivatives Associated With Interest Rate Risk Management Activities (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Customer interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Notional	$ 3,806	$ 3,950
Assets	113	207
Liabilities	36	7
Offsetting upstream interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Notional	3,806	3,950
Assets	3	2
Liabilities	17	17
Customer Interest Rate Contracts Hedging \| Hedging Instruments And Hedged Items \| Customer interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Notional	7,745	6,868
Assets	260	436
Liabilities	16	1
Customer Interest Rate Contracts Hedging \| Hedging Instruments And Hedged Items \| Offsetting upstream interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Notional	7,685	6,868
Assets	3	5
Liabilities	$ 26	$ 35

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.

No definition available.

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959

+ Details

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- Definition

Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

+ References

No definition available.

+ Details

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- Definition

Fair value as of the balance sheet date of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities.

+ References

No definition available.

+ Details

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