Recently Issued Accounting Standards (Policies)	6 Months Ended
Jun. 30, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncements, Policy	In May 2014, the FASB issued updated revenue recognition guidance to clarify the principles for recognizing revenue and to develop a common revenue standard for U.S. GAAP and international financial reporting standards. The new standard requires the recognition of revenue to depict the transfer of promised goods to customers in an amount reflecting the consideration the company expects to receive in the exchange. In March 2016, the FASB issued an update clarifying the implementation guidance on principal versus agent considerations. In April 2016, the FASB issued an update clarifying the identification of performance obligations and licensing implementations guidance. In May 2016, the FASB issued an update clarifying guidance in a few narrow areas and added some practical expedients to the guidance. The accounting standards update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, with early application permitted after December 31, 2016. The standard is required to be adopted using either the full retrospective approach or the modified retrospective approach. While early adoption is permitted, we plan to adopt this new standard in the first quarter of 2018 using the modified retrospective approach. Through June 30, 2017, we have made progress on contract reviews, drafting accounting policies and evaluating the new disclosure requirements. We expect that enhanced disclosures will be required under the new standard. Further analysis is planned in 2017 to complete our evaluation of the impact of the new standard. In February 2016, the FASB issued updated lease accounting guidance requiring companies to recognize the assets and liabilities for the rights and obligations created by long-term leases of assets on the balance sheet. The accounting standards update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018. The standard will not apply to our leases of mineral rights. We are continuing to further evaluate the impact of this guidance on our consolidated financial statements and related disclosures.

In May 2014, the FASB issued updated revenue recognition guidance to clarify the principles for recognizing revenue and to develop a common revenue standard for U.S. GAAP and international financial reporting standards. The new standard requires the recognition of revenue to depict the transfer of promised goods to customers in an amount reflecting the consideration the company expects to receive in the exchange. In March 2016, the FASB issued an update clarifying the implementation guidance on principal versus agent considerations. In April 2016, the FASB issued an update clarifying the identification of performance obligations and licensing implementations guidance. In May 2016, the FASB issued an update clarifying guidance in a few narrow areas and added some practical expedients to the guidance. The accounting standards update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, with early application permitted after December 31, 2016. The standard is required to be adopted using either the full retrospective approach or the modified retrospective approach. While early adoption is permitted, we plan to adopt this new standard in the first quarter of 2018 using the modified retrospective approach. Through June 30, 2017, we have made progress on contract reviews, drafting accounting policies and evaluating the new disclosure requirements. We expect that enhanced disclosures will be required under the new standard. Further analysis is planned in 2017 to complete our evaluation of the impact of the new standard.

In February 2016, the FASB issued updated lease accounting guidance requiring companies to recognize the assets and liabilities for the rights and obligations created by long-term leases of assets on the balance sheet. The accounting standards update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018. The standard will not apply to our leases of mineral rights. We are continuing to further evaluate the impact of this guidance on our consolidated financial statements and related disclosures.