RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			$ 20,270	$ 19,747
Other comprehensive income before reclassifications	$ (121)	$ 12	(518)	96
Other-than-temporary impairment not recognized in earnings on debt securities	0	0	(1)	(2)
Amounts reclassified to the Consolidated Statements of Operations	13	0	21	(7)
Net other comprehensive income	(108)	12	(498)	87
Ending balance	20,276	20,109	20,276	20,109
Total AOCI
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(1,210)	(593)	(820)	(668)
Ending balance	(1,318)	(581)	(1,318)	(581)
Net Unrealized (Losses) Gains on Derivatives
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(200)	(76)	(143)	(88)
Other comprehensive income before reclassifications	(26)	(1)	(91)	22
Other-than-temporary impairment not recognized in earnings on debt securities	0	0	0	0
Amounts reclassified to the Consolidated Statements of Operations	11	(2)	19	(13)
Net other comprehensive income	(15)	(3)	(72)	9
Ending balance	(215)	(79)	(215)	(79)
Net Unrealized (Losses) Gains on Debt Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(575)	(128)	(236)	(186)
Other comprehensive income before reclassifications	(95)	13	(427)	74
Other-than-temporary impairment not recognized in earnings on debt securities	0	0	(1)	(2)
Amounts reclassified to the Consolidated Statements of Operations	(2)	(1)	(8)	(2)
Net other comprehensive income	(97)	12	(436)	70
Ending balance	(672)	(116)	(672)	(116)
Employee Benefit Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(435)	(389)	(441)	(394)
Other comprehensive income before reclassifications	0	0	0	0
Other-than-temporary impairment not recognized in earnings on debt securities	0	0	0	0
Amounts reclassified to the Consolidated Statements of Operations	4	3	10	8
Net other comprehensive income	4	3	10	8
Ending balance	$ (431)	$ (386)	$ (431)	$ (386)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount after tax of other than temporary impairment loss (OTTI) on investments in available-for-sale and held-to-maturity debt securities, recognized in other comprehensive loss and attributable to parent entity.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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