GOODWILL - Goodwill Rollforward (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended	6 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2013
Goodwill [Roll Forward]
Beginning balance	$ 6,876us-gaap_Goodwill	$ 11,311us-gaap_Goodwill		$ 11,311us-gaap_Goodwill
Goodwill impairment	0us-gaap_GoodwillImpairmentLoss	(4,435)us-gaap_GoodwillImpairmentLoss	0us-gaap_GoodwillImpairmentLoss
Transfers		0us-gaap_GoodwillTransfers
Adjustments	0us-gaap_GoodwillOtherChanges
Ending balance	6,876us-gaap_Goodwill	6,876us-gaap_Goodwill	11,311us-gaap_Goodwill
Consumer Banking
Goodwill [Roll Forward]
Beginning balance	2,136	6,393		6,393
Goodwill impairment		(4,435)		(4,400)
Transfers		178
Adjustments	0
Ending balance	2,136	2,136
Commercial Banking
Goodwill [Roll Forward]
Beginning balance	4,740	4,918		4,918
Goodwill impairment		0
Transfers		(178)
Adjustments	0
Ending balance	$ 4,740	$ 4,740

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13854-109267

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13777-109266

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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Balance Type:	debit
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- Definition

Amount of other (increase) decrease 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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- Definition

Amount of transfers 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 among segments.

+ References

No definition available.

+ Details

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