INCOME TAXES - Unrecognized tax benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Balance, January 1	$ 146	$ 120	$ 92
Delphi Technologies acquisition	54	0	0
Additions based on tax positions related to current year	14	7	24
Additions for tax positions of prior years	9	26	18
Reductions for closure of tax audits and settlements	0		(8)
Reductions for lapse in statute of limitations	(5)	(6)	0
Unrecognized tax benefits, increase resulting from foreign currency translation	13
Translation adjustment		(1)	(6)
Balance, December 31	$ 231	$ 146	$ 120