RETIREMENT BENEFITS - Sensitivities of Certain Key Assumptions (Details) - Pension Plans - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans
Effect of one-percentage-point increase in discount rates	$ 29	$ 31	$ 26
Effect of one-percentage-point decrease in discount rates	(44)	(47)	(44)
Effect of one-percentage-point increase on benefits earned and interest cost for U.S. postretirement plans	(127)	(127)	(128)
Effect of one-percentage-point decrease on benefits earned and interest cost for U.S. postretirement plans	127	127	128
Non-U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans
Effect of one-percentage-point increase in discount rates	(27)	(33)	(32)
Effect of one-percentage-point decrease in discount rates	41	37	44
Effect of one-percentage-point increase on benefits earned and interest cost for U.S. postretirement plans	(64)	(61)	(63)
Effect of one-percentage-point decrease on benefits earned and interest cost for U.S. postretirement plans	$ 64	$ 61	$ 63

The effect of a one-percentage-point decrease in the discount rates on pension expenses.

No definition available.

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- Definition

The effect of a one-percentage-point decrease in the expected rates of return on pension expenses.

+ References

No definition available.

+ Details

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- Definition

The effect of a one-percentage-point increase in the discount rates on pension expenses.

+ References

No definition available.

+ Details

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- Definition

The effect of a one-percentage-point increase in the expected rates of return on pension expenses.

+ References

No definition available.

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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