Loans - By Portfolio Segment (Details) $ in Millions	3 Months Ended
Mar. 31, 2019 USD ($) loan_segment	Dec. 31, 2018 USD ($)	Mar. 31, 2018 USD ($)
Receivables [Abstract]
Number of portfolio segments \| loan_segment	3
Loan balances by portfolio segment:
Retained loans	$ 943,841	$ 969,415	$ 925,611
Held-for-sale	8,685	11,988
At fair value	3,719	3,151
Total	956,245	984,554
Consumer, excluding credit card
Loan balances by portfolio segment:
Retained loans	359,715	373,637	373,243
Held-for-sale	4,199	95
At fair value	0	0
Total	363,914	373,732
Credit card
Loan balances by portfolio segment:
Retained loans	150,515	156,616
Held-for-sale	12	16
At fair value	0	0
Total	150,527	156,632
Wholesale
Loan balances by portfolio segment:
Retained loans	433,611	439,162	$ 412,020
Held-for-sale	4,474	11,877
At fair value	3,719	3,151
Total	$ 441,804	$ 454,190

Loans Receivable, Net of Deferred Income

No definition available.

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- Definition

Number of Loan Portfolio Segments

+ References

No definition available.

+ Details

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- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

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- Definition

Amount, after allowance for bad debt, of loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

+ References

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- References

No definition available.

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- References

No definition available.

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