FINANCIAL INSTRUMENTS (Investments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Proceeds from sales of available-for-sale securities	$ 1,078	$ 535	$ 565
Gross realized gains	120	58	96
Gross realized losses	(10)	(2)	$ (14)
Contractual Maturities of Debt Securities, Within one year, Amortized Cost	7
Contractual Maturities of Debt Securities, One to five years, Amortized Cost	370
Contractual Maturities of Debt Securities, Six to ten years, Amortized Cost	680
Contractual Maturities of Debt Securities, After ten years, Amortized Cost	284
Contractual Maturities of Debt Securities, Total, Amortized Cost	1,341	1,230
Contractual Maturities of Debt Securities, Within one year, Fair Value	7
Contractual Maturities of Debt Securities, One to five years, Fair Value	378
Contractual Maturities of Debt Securities, Six to ten years, Fair Value	682
Contractual Maturities of Debt Securities, After ten years, Fair Value	305
Contractual Maturities of Debt Securities, Total, Fair Value	1,372	1,253
Cash Equivalents [Member]
Held-to-maturity Securities	1,771	3,934
Money Market Funds, at Carrying Value	$ 509	$ 239