Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Proposed Merger On February 22, 2022, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Pegasus Holdings III, LLC (“Parent”) and Pegasus Merger Co., a wholly owned subsidiary of Parent (“Merger Sub” and together with Parent, “Buyer”). Pursuant to the terms and conditions set forth in the Merger Agreement, Merger Sub will merge with and into Tenneco (the “Merger”) with Tenneco continuing as the surviving corporation of the Merger and as a wholly owned subsidiary of Parent. At the effective time of the Merger (the “Effective Time”), each share of the Company’s Class A voting common stock that is issued and outstanding immediately prior to the Effective Time (other than shares to be cancelled pursuant to the Merger Agreement or shares of common stock held by holders who have made a valid demand for appraisal in accordance with Section 262 of the Delaware General Corporation Law), will be automatically converted into the right to receive $20.00 in cash, without interest. At the Effective Time, subject to the terms and conditions set forth in the Merger Agreement, each restricted share unit award (“RSU”) and each performance share unit award (“PSU”) of Tenneco that is outstanding immediately prior to the Effective Time will automatically be cancelled and converted into the holder’s right to receive a cash amount (subject to any applicable withholding taxes) calculated based on the per-share Merger consideration of $20.00. The closing of the Merger is subject to various conditions, including (i) the adoption of the Merger Agreement by holders of a majority of the issued and outstanding shares of the Company’s common stock; (ii) the absence of any order, injunction or other legal or regulatory restraint making illegal, enjoining or otherwise prohibiting the closing of the Merger; (iii) the expiration or early termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, or HSR Act and the expiration of any waiting period under other applicable competition and/or foreign laws; (iv) the accuracy of the representations and warranties contained in the Merger Agreement, subject to customary materiality qualifications; and (v) compliance with the covenants and agreements contained in the Merger Agreement as of the closing of the Merger. In addition, the obligation of Parent and Merger Sub to consummate the Merger is subject to the absence, since the date of the Merger Agreement, of a Company Material Adverse Effect (as defined in the Merger Agreement under clause (b) of such definition). The closing of the Merger is not subject to a financing condition, and Parent has obtained equity and debt financing commitments for the purpose of financing the Merger and the other transactions contemplated by the Merger Agreement. The Company’s Board of Directors and the sole member or board of directors, as applicable, of Parent and Merger Sub have each unanimously approved the Merger and the Merger Agreement. If approved by the Company’s stockholders, the Merger is expected to close in the second half of 2022. Until the closing, the Company will continue to operate as an independent company. The Company will incur certain significant costs relating to the Merger, such as legal, accounting, financial advisory, printing and other professional services fees, as well as other customary payments. In the event that the merger is terminated, the Company may also be required to pay a cash termination fee to Parent of $54 million, as required under the Merger Agreement under certain circumstances.