Recent Transactions and Events	9 Months Ended
Recent Transactions and Events	Sep. 30, 2020
Business Combinations [Abstract]
Recent Transactions and Events	Recent Transactions and Events Acquisition of Delphi Technologies PLC On October 1, 2020, the Company completed the acquisition of 100% of the outstanding ordinary shares of Delphi Technologies pursuant to a transaction agreement dated January 28, 2020, as amended on May 6, 2020. Pursuant to the terms of the agreement, the Company issued, in exchange for each Delphi Technologies share, 0.4307 of a share of common stock of the Company, par value $0.01 per share and cash in lieu of any fractional share. In the aggregate, the Company delivered consideration of approximately $2.4 billion, including 37 million shares of common stock, valued at $1.5 billion, repayment of debt of approximately $900 million and stock-based compensation of approximately $15 million. Upon closing, the Company also assumed approximately $800 million in senior notes as discussed below. The acquisition is expected to strengthen the Company’s electronics and power electronics products, capabilities and scale, position the Company for greater growth as electrified propulsion systems gain momentum and enhance key combustion, commercial vehicle and aftermarket businesses. The initial accounting for the business combination is incomplete as of the time of this filing due to the limited amount of time since the acquisition date and the ongoing status of the valuation. Therefore, it is impracticable for the Company to provide the major classes of assets acquired and liabilities assumed as of the closing date or pro forma revenue and earnings. On October 5, 2020, the Company completed its offer to exchange approximately $800 million in aggregate principal amount of the outstanding 5.000% Senior Notes due 2025 (“DT Notes”) of Delphi Technologies. Approximately $776 million in aggregate principal amount of outstanding DT Notes, representing 97% of the $800 million total outstanding principal amount of the DT Notes, were validly exchanged and cancelled for new BorgWarner notes. Following such cancellation, approximately $24 million in aggregate principal amount of the DT Notes will remain outstanding. Since the majority of the notes were exchanged, the Company was able to eliminate substantially all of the restrictive covenants and events of default not related to payment on the $800 million in outstanding Senior Notes. Romeo Systems, Inc. In May 2019, the Company invested $50 million in exchange for a 20% equity interest in Romeo, a technology-leading battery module and pack supplier. The Company accounts for this investment in Series A-1 Preferred Stock of Romeo under the measurement alternative in ASC Topic 321, "Investments - Equity Securities" for equity investments without a readily determinable fair value. Such investments are measured at cost, less any impairment, plus or minus changes resulting from observable price changes in orderly transactions for an identical or similar investment of the same issuer. During the three months ended March 31, 2020, after completing a qualitative assessment which indicated the Company's equity investment in Romeo may have been impaired, the Company recorded a $9 million asset impairment cost to record this investment at its fair value of $41 million. The estimated fair value of Romeo was determined using unobservable inputs including quantitative information from lower valuations in recently completed or proposed financings and the liquidation preferences included in the Romeo stock agreements. These unobservable inputs are considered Level 3. On October 5, 2020, Romeo entered into a definitive merger agreement with RMG Acquisition Corp., a company listed on the New York Stock Exchange. Upon the closing of this transaction, which is subject to closing conditions, the Company’s ownership in Romeo will be reduced and the investment adjusted to fair value. This event had no impact on the carrying value of the Company's investment at September 30, 2020. In September 2019, the Company and Romeo contributed total equity of $10 million and formed a new joint venture, BorgWarner Romeo Power LLC (the "Romeo JV"), in which the Company owns a 60% interest. BorgWarner Morse TEC LLC Like many other industrial companies that have historically operated in the United States, the Company, or parties that the Company was obligated to indemnify, had been named as one of many defendants in asbestos-related personal injury actions. On October 30, 2019, the Company entered into a Membership Interest Purchase Agreement (the "Purchase Agreement") with Enstar Holdings (US) LLC ("Enstar"). Pursuant to the Purchase Agreement, the Company transferred 100% of the equity interests of BorgWarner Morse TEC LLC ("Morse TEC") to Enstar. As Morse TEC was the obligor for the Company's asbestos-related liabilities and policyholder of the related insurance assets, the rights and obligations related to these items transferred upon the sale, and pursuant to the Purchase Agreement, Morse TEC has indemnified the Company and its affiliates for asbestos-related liabilities as more specifically described in the Purchase Agreement. This indemnification obligation with respect to Asbestos-Related Liabilities (as such term is defined in the Purchase Agreement) is not subject to any cap or time limitation. Following the completion of this transfer, the Company has no obligation with respect to previously recorded asbestos-related liabilities. In accordance with ASC Topic 810, "Consolidation," this subsidiary was derecognized as the Company ceased to control the entity, and the Company removed the associated assets and liabilities from the consolidated balance sheet. Rinehart Motion Systems LLC and AM Racing LLC On January 2, 2019, the Company acquired Rinehart Motion Systems LLC and AM Racing LLC, two established companies in the specialty electric and hybrid propulsion market, for approximately $15 million, of which $10 million was paid during the first three months of 2019, $2 million was paid during the first three months of 2020 and the remaining $3 million will be paid upon satisfaction of certain conditions. The Company created Cascadia Motion LLC ("Cascadia Motion") to combine assets and operations of these two acquired companies. Based in Oregon, Cascadia Motion specializes in design, development and production of hybrid and electric propulsion solutions for prototype and low-volume production applications. It allows the Company to offer design, development and production of full electric and hybrid propulsion systems for niche and low-volume manufacturing applications.