Securitizations and Variable Interest Entities (Schedule of Variable Interest Entities) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Variable Interest Entity [Line Items]
Securitization or asset-backed financing arrangement, financial asset for which transfer is accounted as sale, gain on sale	$ 0	$ 0
Variable interest entity, assets deconsolidated	(957)		$ (1,235)
Variable interest entity, carrying value of assets for which we have continuing involvement	26,751		28,195
Variable interest entity, carrying value of liabilities for which we have continuing involvement	10,120		10,845
Variable interest entity, maximum loss exposure	2,110		2,334
Commercial portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, nonconsolidated, carrying amount, assets	867		806
Variable interest entity, nonconsolidated, carrying amount, liabilities	343		326
Variable interest entity, assets deconsolidated	0		0
Variable interest entity, maximum loss exposure	1,115		1,054
Automobile loan \| Consumer portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	16,226		16,255
Variable interest entity, consolidated, carrying amount, liabilities	6,480		6,573
Variable interest entity, nonconsolidated, carrying amount, assets	38		45
Variable interest entity, nonconsolidated, carrying amount, liabilities	0		0
Variable interest entity, assets deconsolidated	(957)		(1,235)
Variable interest entity, maximum loss exposure	995		1,280
Automobile loan \| Consumer portfolio segment \| Held-to-maturity securities
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	36		43
Automobile loan \| Consumer portfolio segment \| Other assets
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	2		2
Automobile loan \| Commercial portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	9,620		11,089
Variable interest entity, consolidated, carrying amount, liabilities	3,297		3,946
Unencumbered \| Automobile loan \| Consumer portfolio segment
Variable Interest Entity [Line Items]
Variable interest entity, consolidated, carrying amount, assets	8,400		8,400
Variable interest entity, consolidated, carrying amount, liabilities	$ 24		$ 25

Assets of nonconsolidated variable interest entities

No definition available.

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- Definition

The carrying amount of the assets in the reporting entity's statement of financial position that relate to consolidated and nonconsolidated Variable Interest Entities.

+ References

No definition available.

+ Details

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- Definition

Carrying value of liabilities for VIEs for which we have continuing involvement

+ References

No definition available.

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- Definition

Reflects, by transferred financial asset type, the amount of sales proceeds in excess of or deficient from the sum of the carrying amounts of transferred financial assets plus transaction costs, including those transactions in which the seller/transferor has continuing involvement with the financial assets that have been transferred.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 10
-Section 40
-Paragraph 4
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- Definition

The carrying amount of the consolidated Variable Interest Entity's assets included in the reporting entity's statement of financial position.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
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-Paragraph 3
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- Definition

The carrying amount of the consolidated Variable Interest Entity's liabilities included in the reporting entity's statement of financial position.

+ References

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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
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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

No definition available.

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- Definition

Carrying amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

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

Carrying amount of the liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

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