Notes Payable and Long-Term Debt (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Apr. 09, 2009	Apr. 06, 2009
Long-term Debt, by Current and Noncurrent [Abstract]
Total long-term debt	$ 1,132,800,000	$ 1,058,000,000
Less: current portion	(381,500,000)	(6,100,000)
Long-term debt, net of current portion	751,300,000	1,051,900,000
Long-term debt, weighted average interest rate	5.90%	6.40%
Estimated fair value of senior unsecured notes	1,454,400,000	1,482,300,000
Fair value higher than carrying value for senior unsecured notes	435,500,000	483,700,000
Outstanding letters of credit	50,000,000	26,500,000
Total Short Term Debt [Member]
Short-term Borrowings [Abstract]
Total short-term debt	196,300,000	122,400,000
Short Term Borrowings [Member]
Short-term Borrowings [Abstract]
Total short-term debt	116,300,000	42,400,000
Receivables Securitization [Member]
Short-term Borrowings [Abstract]
Total short-term debt	80,000,000	80,000,000
Convertible Senior Notes Due April 2012 [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Total long-term debt	368,500,000	348,500,000
Less: current portion	(368,500,000)
Debt instrument maturity period	Apr. 15, 2012
Debt instrument, face amount			373,800,000
Debt instrument, interest rate, stated percentage	3.50%		3.50%
Debt instrument, unamortized premium	36,500,000
Debt instrument, convertible, effective interest rate	9.365%
Debt instrument, convertible, interest expense	33,100,000	31,300,000
Amortization of debt discount (premium)	20,000,000	18,300,000
Debt instrument, periodic payment, interest	6,500,000
Conversion of notes in multiples of principal amount	1,000
Initial conversion rate for notes			30.4706
Per principal amount of notes for initial conversion rate	1,000
Debt instrument conversion price			$ 32.82
Conversion premium				27.50%
BorgWarner Inc. stock price - April 6, 2009				$ 25.74
Debt instrument, convertible, if-converted value in excess of principal	352,100,000	450,200,000
Bond hedge overlay at net pre-tax cost			25,200,000
Conversion premium after bond hedge overlay			50.00%
Conversion price per share after bond hedge overlay			$ 38.61
Senior Notes Due November 2016 [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Total long-term debt	149,500,000	149,400,000
Debt instrument maturity period	Nov. 01, 2016
Debt instrument, face amount	150,000,000
Debt instrument, interest rate, stated percentage	5.80%
Senior Notes Due October 2019 [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Total long-term debt	133,900,000	133,900,000
Debt instrument maturity period	Oct. 01, 2019
Debt instrument, face amount	134,000,000
Debt instrument, interest rate, stated percentage	8.00%
Senior Notes Due September 2020 [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Total long-term debt	247,700,000	247,500,000
Debt instrument maturity period	Sep. 15, 2020
Debt instrument, face amount	250,000,000
Debt instrument, interest rate, stated percentage	4.625%
Senior Notes Due February 2029 [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Total long-term debt	119,300,000	119,300,000
Debt instrument maturity period	Feb. 15, 2029
Debt instrument, face amount	121,000,000
Debt instrument, interest rate, stated percentage	7.125%
Multi Currency Revolving Credit Facility [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Total long-term debt	70,000,000	0
Term Loan Facilities And Other [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Total long-term debt	19,800,000	31,600,000
Unamortized portion of debt derivative [Member]
Long-term Debt, by Current and Noncurrent [Abstract]
Total long-term debt	$ 24,100,000	$ 27,800,000