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EMPLOYEE BENEFIT PLANS - PLAN ASSETS (Details) - Qualified Defined Benefit [Member] - USD ($) $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan asset allocations | 100.00% | 100.00% |
Defined Benefit Plan, Assets, Target Allocations [Abstract] |  |  |
Plan Assets | $ 2,083 | $ 1,846 | $ 1,737
Level 1 [Member] |  |  |
Defined Benefit Plan, Assets, Target Allocations [Abstract] |  |  |
Plan Assets | $ 1,973 | $ 1,752 |
Equity funds [Member] | U.S. |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan asset allocations | 25.00% | 30.00% |
Defined Benefit Plan, Assets, Target Allocations [Abstract] |  |  |
Equities, Range Minimum | 5.00% |  |
Equities, Range Maximum | 33.00% |  |
Equity funds [Member] | U.S. | Level 1 [Member] |  |  |
Defined Benefit Plan, Assets, Target Allocations [Abstract] |  |  |
Plan Assets | $ 515 | $ 545 |
Equity funds [Member] | Non-U.S. [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan asset allocations | 11.00% | 12.00% |
Defined Benefit Plan, Assets, Target Allocations [Abstract] |  |  |
Equities, Range Minimum | 1.00% |  |
Equities, Range Maximum | 16.00% |  |
Equity funds [Member] | Non-U.S. [Member] | Level 1 [Member] |  |  |
Defined Benefit Plan, Assets, Target Allocations [Abstract] |  |  |
Plan Assets | $ 226 | $ 218 |
Credit bond index fund [Member] | Level 1 [Member] |  |  |
Defined Benefit Plan, Assets, Target Allocations [Abstract] |  |  |
Plan Assets | $ 1,232 | $ 989 |
Fixed Income Funds [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan asset allocations | 59.00% | 53.00% |
Defined Benefit Plan, Assets, Target Allocations [Abstract] |  |  |
Equities, Range Minimum | 48.00% |  |
Equities, Range Maximum | 95.00% |  |
Real Estate [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan asset allocations | 4.00% | 5.00% |
Defined Benefit Plan, Assets, Target Allocations [Abstract] |  |  |
Equities, Range Minimum | 2.00% |  |
Equities, Range Maximum | 8.00% |  |
Real Estate [Member] | Level 3 [Member] |  |  |
Defined Benefit Plan, Assets, Target Allocations [Abstract] |  |  |
Plan Assets | $ 97 | $ 91 |
Cash Equivalents [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan asset allocations | 1.00% | 0.00% |
Cash Equivalents [Member] | Level 1 [Member] |  |  |
Defined Benefit Plan, Assets, Target Allocations [Abstract] |  |  |
Plan Assets | $ 13 | $ 3 |

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