Notes Payable and Long-Term Debt (Details) (USD $)	0 Months Ended										3 Months Ended		12 Months Ended		3 Months Ended		3 Months Ended		3 Months Ended		3 Months Ended
	Apr. 16, 2012	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Mar. 31, 2012 Short Term Borrowings [Member]	Dec. 31, 2011 Short Term Borrowings [Member]	Mar. 31, 2012 Receivables Securitization [Member]	Dec. 31, 2011 Receivables Securitization [Member]	Mar. 31, 2012 Total Short Term Debt [Member]	Dec. 31, 2011 Total Short Term Debt [Member]	Mar. 31, 2012 3.50 % Convertible Notes [Member]	Mar. 31, 2011 3.50 % Convertible Notes [Member]	Dec. 31, 2011 3.50 % Convertible Notes [Member]	Apr. 09, 2009 3.50 % Convertible Notes [Member]	Mar. 31, 2012 5.75% Senior Notes [Member]	Dec. 31, 2011 5.75% Senior Notes [Member]	Mar. 31, 2012 8.00% Senior Notes [Member]	Dec. 31, 2011 8.00% Senior Notes [Member]	Mar. 31, 2012 4.625% Senior Notes [Member]	Dec. 31, 2011 4.625% Senior Notes [Member]	Mar. 31, 2012 7.125% Senior Notes [Member]	Dec. 31, 2011 7.125% Senior Notes [Member]	Mar. 31, 2012 Multi Currency Revolving Credit Facility [Member]	Dec. 31, 2011 Multi Currency Revolving Credit Facility [Member]	Mar. 31, 2012 Term Loan Facilities And Other [Member]	Dec. 31, 2011 Term Loan Facilities And Other [Member]	Mar. 31, 2012 Unamortized portion of debt derivative [Member]	Dec. 31, 2011 Unamortized portion of debt derivative [Member]
Short-term debt
Short-term Borrowings					$ 104,200,000	$ 116,300,000	$ 80,000,000	$ 80,000,000	$ 184,200,000	$ 196,300,000
Long-term debt
Long-term Debt		1,225,800,000	1,132,800,000								370,600,000		368,500,000		149,500,000	149,500,000	133,900,000	133,900,000	247,700,000	247,700,000	119,300,000	119,300,000	170,000,000	70,000,000	11,700,000	19,800,000	23,100,000	24,100,000
Current portion of long-term debt		377,100,000	381,500,000
Long-term debt, net of current portion		848,700,000	751,300,000
Debt instrument par value														373,800,000
Debt instrument stated interest rate		3.50%		3.50%							3.50%				5.75%		8.00%		4.625%		7.125%
Debt instrument maturity date											Apr. 15, 2012				Nov. 01, 2016		Oct. 01, 2019		Sep. 15, 2020		Feb. 15, 2029
Debt weighted average interest rate		5.70%	5.90%
Multi-currency revolving credit facility, current borrowing capacity																							650,000,000
Multi-currency revolving credit facility, maximum borrowing capacity																							1,000,000,000
Capital in excess of par, equity component of convertible debt											36,500,000
Effective interest rate of convertible senior notes											9.365%
Interest expense											7,600,000	8,000,000
Amortization of Debt Discount (Premium)											4,400,000	4,800,000
Semi-annually payment of interest for notes											6,500,000
Per principal amount of notes for initial conversion rate											1,000
Initial conversion rate for notes											30.4706
Debt instrument conversion price											$ 32.82
Debt Instrument, Convertible, If-converted Value in Excess of Principal											581,700,000		352,100,000
Conversion premium											27.50%
BorgWarner Inc. stock price - April 6, 2009											$ 25.74
Bond hedge overlay at a 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
Conversion of convertible securities, shares issued	11,400,000
Conversion of convertible securities, value of shares issued	617,300,000
Debt Conversion, Original Debt, Amount	374,000,000
Adjustments to additional paid in capital, equity component of convertible debt, subsequent adjustments	243,500,000
Treasury stock received from bond hedge, shares	6,500,000
Treasury stock received from bond hedge, value	503,900,000
Adjustments to Additional Paid in Capital, Convertible Bond Hedge	504,000,000
Estimated fair value of senior unsecured notes		1,706,500,000	1,454,400,000
Fair value higher than carrying value for senior unsecured notes		685,500,000	435,500,000
Outstanding letter of credit		$ 50,000,000	$ 50,000,000