PENSION AND POSTRETIREMENT BENEFIT PLANS (Fair Value Disclosures) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	$ 6,281	$ 5,322
Plan assets measured at NAV	833	840
Total plan assets at fair value	$ 7,114	6,162
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Percentage of U.S. pension plan equity investments that are actively managed	90.00%
The percentage of employer common stock in total plan assets is less than	1.00%
Equity Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	$ 799	833
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Target allocation percentage of assets	43.00%
Equity Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	$ 1,518	1,368
Plan assets measured at NAV	488	476
Fixed Income Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	724	804
Corporate Debt Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	1,919	1,405
U.S. Treasury and Agency Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	729	536
Short-Term Investment Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	135	90
Insurance Contracts [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	138	112
Cash and Cash Equivalents [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	214	81
Other[Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	105	93
Plan assets measured at NAV	191	166
Venture Capital and Limited Partnerships [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets measured at NAV	$ 154	198
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Target allocation percentage of assets	7.00%
United States Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Target allocation percentage of assets	13.00%
International Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Target allocation percentage of assets	16.00%
Global Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Target allocation percentage of assets	14.00%
Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Target allocation percentage of assets	50.00%
Fair Value Level 1 [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	$ 1,173	1,052
Fair Value Level 1 [Member] | Equity Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	799	833
Fair Value Level 1 [Member] | Equity Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	160	138
Fair Value Level 1 [Member] | Cash and Cash Equivalents [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	214	81
Fair Value Level 2 [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	4,957	4,158
Fair Value Level 2 [Member] | Equity Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	1,358	1,230
Fair Value Level 2 [Member] | Fixed Income Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	724	804
Fair Value Level 2 [Member] | Corporate Debt Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	1,919	1,405
Fair Value Level 2 [Member] | U.S. Treasury and Agency Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	729	536
Fair Value Level 2 [Member] | Short-Term Investment Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	135	90
Fair Value Level 2 [Member] | Other[Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	92	93
Fair Value Level 3 [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	151	112
Fair Value Level 3 [Member] | Insurance Contracts [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	138	$ 112
Fair Value Level 3 [Member] | Other[Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Plan assets subject to leveling	$ 13