RETIREMENT BENEFITS - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Change in accumulated other comprehensive income (loss)
Change, net of tax	$ 12	$ (360)	$ (480)	$ 128
Pension Plans and Postretirement Benefit Plans
Change in accumulated other comprehensive income (loss)
Beginning-of-period balance, net of tax	(5,608)		(5,116)
Actuarial assumptions changes and plan experience	(415)		(1,962)
Net asset gain due to difference between actual and expected returns	367		1,038
Net amortization	64		179
Prior service cost	0		33
Curtailment/settlement gain	(2)		(2)
Foreign exchange impact and other	(3)		(33)
Change in deferred taxes, net	1		267
Change, net of tax	12		(480)
End-of-period balance, net of tax	$ (5,596)		$ (5,596)