FINANCIAL INSTRUMENTS (Temporarily Impaired Securities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Temporarily Impaired Securities, Less than 12 Months, Fair Value	$ 465	$ 592
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months	(8)	(22)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	233	179
Available-for-sale Securities, Continuous Unrealized Loss Position, More than 12 Months	(32)	(45)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	698	771
Available-for-sale Securities, Continuous Unrealized Position	(40)	(67)
Cost method investments, aggregate cost	121	120
Cost method investments, reduction in cost basis due to impairment		4
Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Temporarily Impaired Securities, Less than 12 Months, Fair Value	295	351
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months	(4)	(12)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	151	0
Available-for-sale Securities, Continuous Unrealized Loss Position, More than 12 Months	(7)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	446	351
Available-for-sale Securities, Continuous Unrealized Position	(11)	(12)
Corporate Bonds - Investment Grade [Member]
Schedule of Available-for-sale Securities [Line Items]
Temporarily Impaired Securities, Less than 12 Months, Fair Value	163	193
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months	(2)	(4)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	19	16
Available-for-sale Securities, Continuous Unrealized Loss Position, More than 12 Months	(1)	(1)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	182	209
Available-for-sale Securities, Continuous Unrealized Position	(3)	(5)
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Temporarily Impaired Securities, Less than 12 Months, Fair Value	7	48
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months	(2)	(6)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	63	163
Available-for-sale Securities, Continuous Unrealized Loss Position, More than 12 Months	(24)	(44)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	70	211
Available-for-sale Securities, Continuous Unrealized Position	(26)	(50)
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities	$ 0	$ 0