FAIR VALUE MEASUREMENTS (Schedule of Unrealized Gains (Losses) Related to Available-for-Sale Investments) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 2,270	$ 2,180
Total Unrealized Gains	2,178	2,033
Total Unrealized Losses	(11)	(4)
Total Fair Value	4,437	4,209
Amount primarily related to deferred taxes on appreciation of investment value	740	671
Short-term investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	10	27
Total Unrealized Gains	0	0
Total Unrealized Losses	0	0
Total Fair Value	10	27
Global equity securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	508	543
Total Unrealized Gains	2,064	1,881
Total Unrealized Losses	(2)	(1)
Total Fair Value	2,570	2,423
Fixed-income securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,752	1,610
Total Unrealized Gains	114	152
Total Unrealized Losses	(9)	(3)
Total Fair Value	$ 1,857	$ 1,759