EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 96	$ 111	$ 408	$ 142
Weighted average shares of common stock outstanding (in shares)	238,200,000	206,000,000.0	238,000,000.0	205,900,000
Basic earnings per share of common stock (in dollar per share)	$ 0.40	$ 0.54	$ 1.71	$ 0.69
Diluted earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 96	$ 111	$ 408	$ 142
Weighted average shares of common stock outstanding (in shares)	238,200,000	206,000,000.0	238,000,000.0	205,900,000
Effect of stock-based compensation (in shares)	1,600,000	1,300,000	1,300,000	800,000
Weighted average shares of common stock outstanding including dilutive shares (in shares)	239,800,000	207,300,000	239,300,000	206,700,000
Diluted earnings per share of common stock (in dollar per share)	$ 0.40	$ 0.53	$ 1.70	$ 0.69
Antidilutive securities excluded from computation of earnings per share (in shares)	0	0	0	0
Performance Shares
Diluted earnings per share:
Antidilutive securities excluded from computation of earnings per share (in shares)	647,057	113,532	783,799	113,532