Condensed Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Net earnings attributable to BorgWarner Inc.	$ 158.0	$ 124.5
Foreign currency translation adjustments	44.8	91.2
Market value change of hedge instruments	14.2	(4.5)
Income taxes associated with the market value change of hedge instruments	(5.1)	0.7
Hedge instrument adjustments - (Gain) loss reclassified into net earnings	0.7	0.2
Hedge instruments adjustments - Income taxes reclassified into net earnings	(0.2)	(0.2)
Net change in hedge instruments	9.6	(3.8)
Defined benefit post employment plans - Amortization of prior service benefit and net loss into net earnings	2.2	2.0
Defined benefit post employment plans - Income taxes reclassified into net earnings	(0.6)	(0.6)
Defined benefit post employment plans - Acquisition	0	(5.4)
Defined benefit post employment plans - Income taxes associated with acquisition	0	1.4
Net change in defined benefit post employment plans	1.6	(2.6)
Comprehensive income	214.0	209.3
Comprehensive income (loss) attributable to noncontrolling interest	(0.9)	(1.4)
Comprehensive income (loss) attributable to BorgWarner Inc.	$ 214.9	$ 210.7