Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Net sales	$ 2,694.0	$ 2,389.7	$ 5,478.3	$ 4,796.7
Cost of sales	2,114.8	1,876.8	4,307.3	3,767.5
Gross profit	579.2	512.9	1,171.0	1,029.2
Selling, general and administrative expenses	236.0	215.1	489.4	434.1
Other expense (income), net	30.4	(0.3)	35.3	5.5
Operating income	312.8	298.1	646.3	589.6
Equity in affiliates’ earnings, net of tax	(13.0)	(14.4)	(23.2)	(24.1)
Interest income	(1.4)	(1.4)	(2.9)	(2.9)
Interest expense and finance charges	14.9	18.0	31.0	36.0
Other postretirement income	(2.4)	(1.4)	(5.0)	(2.6)
Earnings before income taxes and noncontrolling interest	314.7	297.3	646.4	583.2
Provision for income taxes	30.4	76.2	125.3	162.5
Net earnings	284.3	221.1	521.1	420.7
Net earnings attributable to the noncontrolling interest, net of tax	12.5	9.1	24.2	19.5
Net earnings attributable to BorgWarner Inc.	$ 271.8	$ 212.0	$ 496.9	$ 401.2
Earnings per share — basic	$ 1.30	$ 1.01	$ 2.38	$ 1.90
Earnings per share — diluted	$ 1.30	$ 1.00	$ 2.36	$ 1.89
Weighted average shares outstanding (thousands):
Basic	208,570	210,572	209,023	211,084
Diluted	209,857	211,478	210,312	211,857
Dividends declared per share	$ 0.17	$ 0.14	$ 0.34	$ 0.28