Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Basic earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 271.8	$ 212.0	$ 496.9	$ 401.2
Weighted average shares of common stock outstanding	208,570,000	210,572,000	209,023,000	211,084,000
Basic earnings per share of common stock	$ 1.30	$ 1.01	$ 2.38	$ 1.90
Diluted earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 271.8	$ 212.0	$ 496.9	$ 401.2
Weighted average shares of common stock outstanding	208,570,000	210,572,000	209,023,000	211,084,000
Effect of stock-based compensation	1,287,000	906,000	1,289,000	773,000
Weighted average shares of common stock outstanding including dilutive shares	209,857,000	211,478,000	210,312,000	211,857,000
Diluted earnings per share of common stock	$ 1.30	$ 1.00	$ 2.36	$ 1.89
Awards Granted in 2016 [Member] | Performance Shares [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	174,400		174,400
Awards Granted in 2018 [Member] | Performance Shares [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	174,750		174,750