FAIR VALUE MEASUREMENTS (Other Fair Value Narrative) (Details) $ in Millions	Jun. 30, 2019 USD ($) hedge_fund	Dec. 31, 2018 USD ($)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Number of hedge funds with reporting lag | hedge_fund	2
Entities that calculate net asset value per share, reporting lag, percent other investments	64.00%	61.00%
Reported Value Measurement
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	$ 1,388	$ 1,342
Estimate of fair value measurement
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	$ 1,443	$ 1,334