CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Net sales	$ 3,416	$ 2,534	$ 11,183	$ 6,239
Cost of sales	2,766	2,017	8,953	5,101
Gross profit	650	517	2,230	1,138
Selling, general and administrative expenses	343	204	1,084	601
Other operating expense, net	54	29	173	133
Operating income	253	284	973	404
Equity in affiliates’ earnings, net of tax	(12)	(3)	(40)	(10)
Unrealized loss on equity securities	61	0	337	9
Interest income	(3)	(3)	(9)	(8)
Interest expense	21	20	84	50
Other postretirement income	(10)	(2)	(33)	(5)
Earnings before income taxes and noncontrolling interest	196	272	634	368
Provision for income taxes	79	143	149	186
Net earnings	117	129	485	182
Net earnings attributable to noncontrolling interest, net of tax	21	18	77	40
Net earnings attributable to BorgWarner Inc.	$ 96	$ 111	$ 408	$ 142
Earnings per share attributable to BorgWarner Inc. — basic (in dollar per share)	$ 0.40	$ 0.54	$ 1.71	$ 0.69
Earnings per share attributable to BorgWarner Inc. — diluted (in dollar per share)	$ 0.40	$ 0.53	$ 1.70	$ 0.69
Weighted average shares outstanding:
Basic (in shares)	238.2	206.0	238.0	205.9
Diluted (in shares)	239.8	207.3	239.3	206.7