GOODWILL AND INTANGIBLE ASSETS - Components of Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2022	Dec. 31, 2021
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	$ 10,097	$ 10,210
Accumulated amortization of Intangible assets (excluding MSRs)	6,095	6,119
Net carrying amount of Intangible assets (excluding MSRs)	4,002	4,091
Gross carrying amount, Mortgage servicing rights (MSRs)	520	404
Mortgage servicing rights (MSRs)	520	404
Gross carrying amount of Intangible assets	10,617	10,614
Accumulated amortization of Intangible assets	6,095	6,119
Total intangible assets	4,522	4,495
Indefinite-lived intangible assets
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	188	183
Net carrying amount of Intangible assets (excluding MSRs)	188	183
Purchased credit card relationships
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	5,523	5,579
Accumulated amortization of Intangible assets (excluding MSRs)	4,328	4,348
Net carrying amount of Intangible assets (excluding MSRs)	1,195	1,231
Credit card contract related intangibles
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	3,904	3,912
Accumulated amortization of Intangible assets (excluding MSRs)	1,402	1,372
Net carrying amount of Intangible assets (excluding MSRs)	2,502	2,540
Core deposit intangibles
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	38	39
Accumulated amortization of Intangible assets (excluding MSRs)	38	39
Net carrying amount of Intangible assets (excluding MSRs)	0	0
Other customer relationships
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	412	429
Accumulated amortization of Intangible assets (excluding MSRs)	297	305
Net carrying amount of Intangible assets (excluding MSRs)	115	124
Present value of future profits
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	32	31
Accumulated amortization of Intangible assets (excluding MSRs)	30	29
Net carrying amount of Intangible assets (excluding MSRs)	2	2
Other
Finite and Indefinite-lived Intangible Assets
Gross carrying amount of Intangible assets (excluding MSRs)	0	37
Accumulated amortization of Intangible assets (excluding MSRs)	0	26
Net carrying amount of Intangible assets (excluding MSRs)	$ 0	$ 11
Customer Concentration Risk \| American Airlines, Costco, The Home Depot and AT&T \| Intangible Assets, Excluding Mortgage Servicing Rights \| Credit card contract related intangibles
Finite and Indefinite-lived Intangible Assets
Concentration risk, percentage	97.00%	97.00%

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.

+ Details

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- Definition

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.

+ Details

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- Definition

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.

+ Details

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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.

+ References

No definition available.

+ Details

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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.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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