FAIR VALUE MEASUREMENTS (Schedule of Maturities on Debt Securities) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Total maturities of fixed-income securities	$ 3,507	$ 3,138
Fixed-income securities
Debt Securities, Available-for-sale [Line Items]
Less than 1 year	26
1–5 years	541
5–10 years	340
More than 10 years	606
Total maturities of fixed-income securities	$ 1,513	$ 1,300

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