GOODWILL AND INTANGIBLE ASSETS - Components of Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	$ 12,271	$ 12,181
Accumulated amortization of Intangible assets (excluding MSRs)	7,944	7,545
Net carrying amount of intangible assets (excluding MSRs)	4,327	4,636
Gross carrying amount, Mortgage servicing rights (MSRs)	495	584
Mortgage servicing rights (MSRs)	495	584
Gross carrying amount of Intangible assets	12,766	12,765
Accumulated amortization of intangible assets	7,944	7,545
Net carrying amount of intangible assets, balance at end of period	4,822	5,220
Intangible assets amortization expense	564	557	$ 603
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2020	424
2021	399
2022	1,025
2023	226
2024	219
Indefinite-lived intangible assets
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	228	218
Accumulated amortization of Intangible assets (excluding MSRs)	0	0
Net carrying amount of intangible assets (excluding MSRs)	228	218
Purchased credit card relationships
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	5,676	5,733
Accumulated amortization of Intangible assets (excluding MSRs)	4,059	3,936
Net carrying amount of intangible assets (excluding MSRs)	1,617	1,797
Credit card contract related intangibles
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	5,393	5,225
Accumulated amortization of Intangible assets (excluding MSRs)	3,069	2,791
Net carrying amount of intangible assets (excluding MSRs)	2,324	2,434
Core deposit intangibles
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	434	419
Accumulated amortization of Intangible assets (excluding MSRs)	433	415
Net carrying amount of intangible assets (excluding MSRs)	1	4
Other customer relationships
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	424	470
Accumulated amortization of Intangible assets (excluding MSRs)	275	299
Net carrying amount of intangible assets (excluding MSRs)	149	171
Present value of future profits
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	34	32
Accumulated amortization of Intangible assets (excluding MSRs)	31	29
Net carrying amount of intangible assets (excluding MSRs)	3	3
Other
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	82	84
Accumulated amortization of Intangible assets (excluding MSRs)	77	75
Net carrying amount of intangible assets (excluding MSRs)	$ 5	$ 9
American Airlines, Sears, The Home Depot and Costco \| Intangible Assets, Excluding Mortgage Servicing Rights \| Customer Concentration Risk \| Credit card contract related intangibles
Finite and Indefinite-lived Intangible Assets
Intangible assets, percent	96.00%	96.00%

No definition available.

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- Definition

Sum of the carrying amounts of all intangible assets, excluding goodwill and excluding mortgage servicing rights, as of the balance sheet date, net of accumulated amortization and impairment charges.

+ References

No definition available.

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This element represents the accumulated amortization of all intangible assets, excluding goodwill and mortgage servicing rights (MSRs), as of the balance sheet date.

+ References

No definition available.

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This element represents the gross carrying amounts of all intangible assets, excluding goodwill and mortgage servicing rights (MSRs), as of the balance sheet date.

+ References

No definition available.

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This element represents the sum of the carrying amounts of all intangible assets excluding goodwill but including mortgage servicing rights, as of the balance sheet date that is net of accumulated amortization and impairment charges.

+ References

No definition available.

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This element represents the accumulated amortization of all intangible assets excluding goodwill but including mortgage servicing rights (MSRs), as of the balance sheet date.

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No definition available.

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This element represents the gross carrying amount of intangible assets excluding goodwill but including mortgage servicing rights (MSRs), as of the balance sheet date.

+ References

No definition available.

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The amount of mortgage servicing rights (MSRs) as of the balance sheet date.

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This element represents the gross carrying amount of mortgage servicing rights (MSRs) as of the balance sheet date.

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No definition available.

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- Definition

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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