GOODWILL AND INTANGIBLE ASSETS - Changes in Intangible Assets (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2019	Dec. 31, 2018
Finite and Indefinite-lived Intangible Assets
Net carrying amount at December 31, 2018, Intangible assets (excluding MSRs)	$ 4,636
Acquisitions/ divestitures	0
Amortization	(284)
FX translation and other	166
Net carrying amount at June 30, 2019, Intangible assets (excluding MSRs)	4,518	$ 4,636
Mortgage servicing rights (MSRs)	508	584
Total intangible assets	5,026	5,220
Indefinite-lived intangible assets
Finite and Indefinite-lived Intangible Assets
Net carrying amount at December 31, 2018, Intangible assets (excluding MSRs)	218
Acquisitions/ divestitures	0
Amortization	0
FX translation and other	4
Net carrying amount at June 30, 2019, Intangible assets (excluding MSRs)	222	218
Purchased credit card relationships
Finite and Indefinite-lived Intangible Assets
Net carrying amount at December 31, 2018, Intangible assets (excluding MSRs)	1,797
Acquisitions/ divestitures	0
Amortization	(95)
FX translation and other	0
Net carrying amount at June 30, 2019, Intangible assets (excluding MSRs)	1,702	1,797
Credit card contract related intangibles
Finite and Indefinite-lived Intangible Assets
Net carrying amount at December 31, 2018, Intangible assets (excluding MSRs)	2,434
Acquisitions/ divestitures	0
Amortization	(168)
FX translation and other	150
Net carrying amount at June 30, 2019, Intangible assets (excluding MSRs)	2,416	2,434
Core deposit intangibles
Finite and Indefinite-lived Intangible Assets
Net carrying amount at December 31, 2018, Intangible assets (excluding MSRs)	4
Acquisitions/ divestitures	0
Amortization	(4)
FX translation and other	1
Net carrying amount at June 30, 2019, Intangible assets (excluding MSRs)	1	4
Other customer relationships
Finite and Indefinite-lived Intangible Assets
Net carrying amount at December 31, 2018, Intangible assets (excluding MSRs)	171
Acquisitions/ divestitures	0
Amortization	(12)
FX translation and other	4
Net carrying amount at June 30, 2019, Intangible assets (excluding MSRs)	163	171
Present value of future profits
Finite and Indefinite-lived Intangible Assets
Net carrying amount at December 31, 2018, Intangible assets (excluding MSRs)	3
Acquisitions/ divestitures	0
Amortization	0
FX translation and other	0
Net carrying amount at June 30, 2019, Intangible assets (excluding MSRs)	3	3
Other
Finite and Indefinite-lived Intangible Assets
Net carrying amount at December 31, 2018, Intangible assets (excluding MSRs)	9
Acquisitions/ divestitures	0
Amortization	(5)
FX translation and other	7
Net carrying amount at June 30, 2019, Intangible assets (excluding MSRs)	$ 11	$ 9
American Airlines, Sears, The Home Depot, Costco and AT&T \| Customer Concentration Risk \| Intangible Assets, Excluding Mortgage Servicing Rights \| Credit card contract related intangibles
Finite and Indefinite-lived Intangible Assets
Concentration risk, percentage	97.00%	97.00%

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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.

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No definition available.

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Intangible Assets, Excluding Mortgage Servicing Rights Acquisitions (Divestitures)

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No definition available.

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This element represents the aggregate amount of amortization of intangible assets excluding mortgage servicing rights (MSRs) during the period.

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No definition available.

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This element represents net changes to the recorded value of intangible assets excluding mortgage servicing rights (MSRs), due to foreign currency translation adjustments and purchase accounting adjustments.

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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.

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

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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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