Variable Interest Entities (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Variable Interest Entity [Line Items]
Investment securities related to state and political subdivisions	$ 930		$ 940
Variable interest entity, other short-term borrowings	$ 820
Weighted average life of trusts	2 years 8 months 12 days	3 years
Assets	$ 362,527		245,610
Liabilities	338,666		221,179
VIE - primary beneficiary
Variable Interest Entity [Line Items]
Assets	16		21
Liabilities	3		5
Potential maximum loss exposure of unconsolidated funds	13		16
VIE - not primary beneficiary
Variable Interest Entity [Line Items]
Potential maximum loss exposure of unconsolidated funds	$ 20		$ 21

Other Short Term Borrowings, Subdivisions

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- Definition

Variable Interest Entity Fair Value Of Collateralized Assets

+ References

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- Definition

Weighted Average Life Of Trusts

+ References

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- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(11))
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-Section 50
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-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
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-Subparagraph (SX 210.7-03(a)(12))
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- Definition

Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
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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

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