Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Performance shares excluded from diluted earnings per share (in shares)	113,532		113,532
Basic earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 111	$ 194	$ 142	$ 526
Weighted average shares of common stock outstanding (shares)	206,000,000.0	205,300,000	205,900,000	205,900,000
Basic (loss) earnings per share of common stock (in dollar per share)	$ 0.54	$ 0.94	$ 0.69	$ 2.56
Diluted earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 111	$ 194	$ 142	$ 526
Weighted average shares of common stock outstanding (shares)	206,000,000.0	205,300,000	205,900,000	205,900,000
Effect of stock-based compensation (shares)	1,300,000	1,000,000.0	800,000	900,000
Weighted average shares of common stock outstanding including dilutive shares (shares)	207,300,000	206,300,000	206,700,000	206,800,000
Diluted earnings per share of common stock (in dollar per share)	$ 0.53	$ 0.94	$ 0.69	$ 2.54
Antidilutive securities excluded from computation of earnings per share (shares)	0	100,000	0	100,000