Subsequent Event	12 Months Ended
Subsequent Event	Dec. 31, 2017
Subsequent Event [Line Items]
Subsequent Events [Text Block]	Subsequent Event On February 7, 2018, TNCLP announced that, in accordance with Section 17.1 of the TNCLP Partnership Agreement, TNGP elected to exercise the right, assigned to TNGP by TNCLP, to purchase all of the issued and outstanding common units representing limited partner interests in TNCLP not already owned by TNGP or its affiliates (the Public Units). TNGP will purchase the Public Units on April 2, 2018 for a cash purchase price of $84.033 per Public Unit. The purchase price was determined in accordance with Section 17.1 of the TNCLP Partnership Agreement as the average of the daily closing prices per common unit for the 20 consecutive trading days beginning with January 5, 2018 and ending with February 2, 2018. As of April 2, 2018, all rights of the holders of the Public Units will cease, except for the right to receive payment of the purchase price. Upon completion of the purchase on April 2, 2018, TNGP will own 100 percent of the Public Units and will be entitled to all of the benefits resulting from the Public Units. As a result of TNGP’s exercise of the right to purchase the Public Units, there will be no further cash distributions on the common units after the distribution payable February 28, 2018. In addition, upon completion of the purchase, the common units representing limited partner interests in TNCLP will cease to be publicly traded or listed on the NYSE.

TERRA NITROGEN CO L P /DE 10-K