FAIR VALUE MEASUREMENTS (Schedule of Unrealized Gains (Losses) Related to Available-for-Sale Investments) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 2,082	$ 2,011
Total Unrealized Gains	1,834	1,698
Total Unrealized Losses	(12)	(6)
Total Fair Value	3,904	3,703
Amount primarily related to deferred taxes on appreciation of investment value	586	530
Short-term investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	12	6
Total Unrealized Gains	0	0
Total Unrealized Losses	0	0
Total Fair Value	12	6
Global equity securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	584	500
Total Unrealized Gains	1,670	1,609
Total Unrealized Losses	(9)	(2)
Total Fair Value	2,245	2,107
Fixed-income securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,486	1,505
Total Unrealized Gains	164	89
Total Unrealized Losses	(3)	(4)
Total Fair Value	$ 1,647	$ 1,590