Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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The number of businesses acquired by the entity during the period.

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Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment.

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GOODWILL - Narrative (Details) $ in Millions	6 Months Ended	12 Months Ended			216 Months Ended
GOODWILL - Narrative (Details) $ in Millions	Jun. 30, 2013 USD ($)	Dec. 31, 2015 USD ($) reporting_unit	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($) business
Goodwill [Line Items]
Number of acquisitions of banks or assets of banks \| business					25
Number of reporting units \| reporting_unit		2
Goodwill impairment		$ 0	$ 0	$ 4,435
Consumer Banking
Goodwill [Line Items]
Goodwill accumulated impairment loss		5,900	5,900		$ 5,900
Goodwill impairment	$ 4,400
Commercial Banking
Goodwill [Line Items]
Goodwill accumulated impairment loss		$ 50	$ 50		$ 50