INCOME TAXES - Foreign Earnings (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Foreign pretax earnings	$ 16,100	$ 13,700	$ 11,600
Foreign pretax loss recorded in discontinued operations	0
Accumulated undistributed profits of non-U.S. subsidiaries considered indefinitely reinvested	15,500
Additional tax liability to be provided should be undistributed earnings of foreign subsidiaries which were indefinitely invested were remitted currently	4,300
Total bad debt reserved not included in deferred tax liabilities calculation	358
Deferred tax liabilities not recognized relating to bad debt reserved	$ 75