Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net earnings attributable to BorgWarner Inc.		$ 271.8	$ 212.0	$ 496.9	$ 401.2
Other comprehensive income (loss)
Foreign currency translation adjustments		(145.5)	73.4	(80.5)	122.4
Hedge instruments	[1]	1.6	(2.3)	(1.7)	(3.5)
Defined benefit postretirement plans	[1]	6.6	(4.5)	4.6	(4.4)
Other	[1]	0.0	1.2	0.0	1.2
Total other comprehensive income attributable to BorgWarner Inc.		(137.3)	67.8	(77.6)	115.7
Comprehensive income attributable to BorgWarner Inc.		134.5	279.8	419.3	516.9
Net earnings attributable to the noncontrolling interest, net of tax		12.5	9.1	24.2	19.5
Other comprehensive income attributable to the noncontrolling interest		(6.5)	(0.6)	(4.1)	3.4
Comprehensive income		$ 140.5	$ 288.3	$ 439.4	$ 539.8

[1] Net of income taxes.