DERIVATIVE INSTRUMENTS - Gains (Losses) Recognized on Fair Value Hedging Relationships (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Fixed-maturity securities and equity securities \| Foreign currency forwards
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized for derivatives		$ (34)		$ 307
Gains (losses) on derivatives excluded from effectiveness testing		(50)		(98)
Gains (losses) on derivatives included in effectiveness testing		16		405
Gains (losses) recognized for hedged items		(15)		(387)
Ineffectiveness recognized for fair value hedge		1		18
Fixed maturity securities \| Foreign currency forwards
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized for derivatives	$ (215)		$ 199
Gains (losses) on derivatives excluded from effectiveness testing	(30)		(69)
Gains (losses) on derivatives included in effectiveness testing	(185)		268
Gains (losses) recognized for hedged items	186		(278)
Ineffectiveness recognized for fair value hedge	1		(10)
Fixed maturity securities \| Foreign currency options
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses) recognized for derivatives	(2)	(7)	(3)	17
Gains (losses) on derivatives excluded from effectiveness testing	(2)	(7)	(3)	6
Gains (losses) on derivatives included in effectiveness testing	0	0	0	11
Gains (losses) recognized for hedged items	0	0	0	(10)
Ineffectiveness recognized for fair value hedge	$ 0	$ 0	$ 0	$ 1

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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Amount of gain (loss) on derivative instrument designated and qualifying as fair value hedge included in assessment of hedge effectiveness, recognized in earnings.

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-Publisher FASB
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Net gain (loss) relating to components of the gain (loss) on the fair value hedging instrument excluded from the assessment of fair value hedge effectiveness. Recognized in earnings.

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-Publisher FASB
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Amount of gain (loss)recognized in the income statement from the hedging ineffectiveness of a fair value hedge.

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