SECURITIES - Schedule of Securities Under Agreements to Repurchase or Resell Remaining Contractual Maturity (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Assets Under Agreements to Repurchase or Resell
Securities purchased under agreements to resell, gross	$ 500	$ 0
Securities sold under agreements to repurchase	(500)
Mortgage-backed securities - Agency
Assets Under Agreements to Repurchase or Resell
Securities purchased under agreements to resell, gross	500
Securities sold under agreements to repurchase	(500)
Overnight and Continuous
Assets Under Agreements to Repurchase or Resell
Securities purchased under agreements to resell, gross	0
Securities sold under agreements to repurchase	0
Overnight and Continuous \| Mortgage-backed securities - Agency
Assets Under Agreements to Repurchase or Resell
Securities purchased under agreements to resell, gross	0
Securities sold under agreements to repurchase	0
Up to 30 Days
Assets Under Agreements to Repurchase or Resell
Securities purchased under agreements to resell, gross	500
Securities sold under agreements to repurchase	(500)
Up to 30 Days \| Mortgage-backed securities - Agency
Assets Under Agreements to Repurchase or Resell
Securities purchased under agreements to resell, gross	500
Securities sold under agreements to repurchase	(500)
30-90 Days
Assets Under Agreements to Repurchase or Resell
Securities purchased under agreements to resell, gross	0
Securities sold under agreements to repurchase	0
30-90 Days \| Mortgage-backed securities - Agency
Assets Under Agreements to Repurchase or Resell
Securities purchased under agreements to resell, gross	0
Securities sold under agreements to repurchase	0
Greater Than 90 Days
Assets Under Agreements to Repurchase or Resell
Securities purchased under agreements to resell, gross	0
Securities sold under agreements to repurchase	0
Greater Than 90 Days \| Mortgage-backed securities - Agency
Assets Under Agreements to Repurchase or Resell
Securities purchased under agreements to resell, gross	0
Securities sold under agreements to repurchase	$ 0

Carrying amount of assets sold under agreements to repurchase when the carrying amount (or market value, if higher than the carrying amount) of securities or other assets sold under repurchase agreements exceeds 10 percent of total assets.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(m)(1)(i)(A)(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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+ References

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- Definition

Amount, before effects of master netting arrangements, of funds outstanding loaned in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=51825145&loc=SL20226000-175313

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