Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive securities excluded from computation of earnings per share amount	0.1	0.1	0.1	0.1
Basic earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 194	$ 204	$ 526	$ 701
Weighted average shares of common stock outstanding	205.3	207.5	205.9	208.5
Basic earnings per share of common stock	$ 0.94	$ 0.98	$ 2.56	$ 3.36
Diluted earnings per share:
Net earnings attributable to BorgWarner Inc.	$ 194	$ 204	$ 526	$ 701
Weighted average shares of common stock outstanding	205.3	207.5	205.9	208.5
Effect of stock-based compensation	1.0	1.2	0.9	1.3
Weighted average shares of common stock outstanding including dilutive shares	206.3	208.7	206.8	209.8
Diluted earnings per share of common stock	$ 0.94	$ 0.98	$ 2.54	$ 3.34

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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