EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Oct. 01, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Performance shares excluded from diluted earnings per share (in shares)		480,548
Issued acquisition (in shares)	37,000,000
Diluted shares from earnings (in shares)	9,000,000
Basic earnings per share:
Net earnings attributable to BorgWarner Inc.		$ 500	$ 746	$ 931
Weighted average shares of common stock outstanding (in shares)		213,000,000.0	205,700,000	208,200,000
Basic earnings per share of common stock (in dollar per share)		$ 2.35	$ 3.63	$ 4.47
Diluted earnings per share:
Net earnings attributable to BorgWarner Inc.		$ 500	$ 746	$ 931
Effect of stock-based compensation (in shares)		1,000,000.0	1,100,000	1,300,000
Weighted average shares of common stock outstanding including dilutive shares (in shares)		214,000,000.0	206,800,000	209,500,000
Diluted earnings per share of common stock (in dollar per share)		$ 2.34	$ 3.61	$ 4.44
Antidilutive securities excluded from computation of earnings per share ( in shares)			100,000	100,000