Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Basic earnings per share [Abstract]
Net earnings attributable to BorgWarner Inc.	$ 220	$ 194	$ 172	$ 160	$ 230	$ 204	$ 272	$ 225	$ 746	$ 931	$ 440
Weighted average shares of common stock outstanding									205.7	208.2	210.4
Earnings per share — basic	$ 1.07	$ 0.94	$ 0.84	$ 0.77	$ 1.11	$ 0.98	$ 1.30	$ 1.07	$ 3.63	$ 4.47	$ 2.09
Diluted earnings per share [Abstract]
Net earnings attributable to BorgWarner Inc.	$ 220	$ 194	$ 172	$ 160	$ 230	$ 204	$ 272	$ 225	$ 746	$ 931	$ 440
Effect of stock-based compensation									1.1	1.3	1.1
Weighted average shares of common stock outstanding including dilutive shares									206.8	209.5	211.5
Earnings per share — diluted	$ 1.06	$ 0.94	$ 0.83	$ 0.77	$ 1.10	$ 0.98	$ 1.30	$ 1.07	$ 3.61	$ 4.44	$ 2.08
Performance Shares [Member]
Diluted earnings per share [Abstract]
Antidilutive stock-based awards excluded from the calculation of diluted earnings per share									0.1	0.1