INCOME TAXES - Foreign Earnings (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Foreign pretax earnings	$ 13,800	$ 16,700	$ 16,100
Accumulated undistributed profits of non-U.S. subsidiaries considered indefinitely reinvested	11,000
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