FAIR VALUE MEASUREMENTS (Schedule of Unrealized Gains (Losses) Related to Available-for-Sale Investments) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 2,111	$ 2,011
Total Unrealized Gains	1,343	1,698
Total Unrealized Losses	(45)	(6)
Total Fair Value	3,409	3,703
Amount primarily related to deferred taxes on appreciation of investment value	498	530
Short-term investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	82	6
Total Unrealized Gains	0	0
Total Unrealized Losses	0	0
Total Fair Value	82	6
Global equity securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	652	500
Total Unrealized Gains	1,188	1,609
Total Unrealized Losses	(31)	(2)
Total Fair Value	1,809	2,107
Fixed-income securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,377	1,505
Total Unrealized Gains	155	89
Total Unrealized Losses	(14)	(4)
Total Fair Value	$ 1,518	$ 1,590