MORTGAGE BANKING - Residential Mortgage Loans (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residential mortgage loan sold with servicing retained	$ 20,430	$ 8,149	$ 3,161
Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residential mortgage loan sold with servicing retained	20,430	8,149	3,161
Mortgage Banking Fees
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gain on sales	251	89	35
Contractually specified servicing, late and other ancillary fees	$ 208	$ 118	$ 53

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No definition available.

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- Definition

Amount of contractually specified servicing fee, late fee, and ancillary fee recognized as income for servicing asset and servicing liability.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 2
-Subparagraph (c)
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- Definition

The gains (losses) included in earnings that represent the difference between the sale price and the carrying value of loans made to finance real estate acquisitions. This element refers to the gain (loss) and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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The cash inflow from sales of loans that are secured with real estate mortgages and are held with the intention to resell in the near future.

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