RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS	12 Months Ended
Dec. 31, 2016
Disclosure Text Block [Abstract]
RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS	RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS TEP considers the applicability and impact of all accounting standard updates issued by the Financial Accounting Standards Board (FASB). The following updates have been issued, but have not yet been adopted by TEP. Updates not listed below were assessed and determined to be either not applicable or are expected to have minimal impact on the Company's consolidated financial position, results of operations, or disclosures. REVENUE FROM CONTRACTS WITH CUSTOMERS In May 2014, the FASB issued an accounting standard update that will eliminate the transaction and industry-specific revenue recognition guidance under current GAAP and replace it with a principles-based approach for determining revenue recognition. In July 2015, the FASB voted to defer the effective date of the revenue recognition standard by one year, and TEP is required to adopt the new guidance for annual and interim periods beginning January 1, 2018. The Company has elected not to early adopt this standard. The revenue standard requires entities to apply the guidance retrospectively or under the modified retrospective approach by recognizing the cumulative effect of initially applying the guidance as an adjustment to the opening balance of retained earnings supplemented by additional disclosures. TEP expects to use the modified retrospective approach. Retail and wholesale sales of energy based on regulator-approved tariff rates represent TEP’s primary sources of revenue. TEP does not expect that the adoption of this standard will have a material impact on the recognition of revenue from energy sales to retail or wholesale customers. Certain industry specific interpretative issues, including contributions in aid of construction, remain outstanding. The conclusions reached, if different than currently anticipated, could change the Company's expected method of adoption and have a material impact on the Company’s consolidated financial statements and related disclosures. LEASES In February 2016, the FASB issued an accounting standard update that will require the recognition of leased assets and liabilities by lessees for those leases classified as operating leases under current GAAP. The standard is effective for periods beginning January 1, 2019, and is to be applied using a modified retrospective approach with practical expedient options. Early adoption is permitted. TEP is evaluating the impact of this update to its financial statements and disclosures. RESTRICTED CASH In November 2016, the FASB issued an accounting standard update that will require entities to show the changes in the total of cash, cash equivalents, and restricted cash or restricted cash equivalents in the statement of cash flows. As a result, entities will no longer present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. The standard is effective for annual and interim periods beginning January 1, 2018, and is to be applied using a retrospective approach. Early adoption is permitted. TEP is evaluating the impact of this update to its financial statements and disclosures.

RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS

TEP considers the applicability and impact of all accounting standard updates issued by the Financial Accounting Standards Board (FASB). The following updates have been issued, but have not yet been adopted by TEP. Updates not listed below were assessed and determined to be either not applicable or are expected to have minimal impact on the Company's consolidated financial position, results of operations, or disclosures.

REVENUE FROM CONTRACTS WITH CUSTOMERS

In May 2014, the FASB issued an accounting standard update that will eliminate the transaction and industry-specific revenue recognition guidance under current GAAP and replace it with a principles-based approach for determining revenue recognition. In July 2015, the FASB voted to defer the effective date of the revenue recognition standard by one year, and TEP is required to adopt the new guidance for annual and interim periods beginning January 1, 2018. The Company has elected not to early adopt this standard.

The revenue standard requires entities to apply the guidance retrospectively or under the modified retrospective approach by recognizing the cumulative effect of initially applying the guidance as an adjustment to the opening balance of retained earnings supplemented by additional disclosures. TEP expects to use the modified retrospective approach.

Retail and wholesale sales of energy based on regulator-approved tariff rates represent TEP’s primary sources of revenue. TEP does not expect that the adoption of this standard will have a material impact on the recognition of revenue from energy sales to retail or wholesale customers. Certain industry specific interpretative issues, including contributions in aid of construction, remain outstanding. The conclusions reached, if different than currently anticipated, could change the Company's expected method of adoption and have a material impact on the Company’s consolidated financial statements and related disclosures.

LEASES

In February 2016, the FASB issued an accounting standard update that will require the recognition of leased assets and liabilities by lessees for those leases classified as operating leases under current GAAP. The standard is effective for periods beginning January 1, 2019, and is to be applied using a modified retrospective approach with practical expedient options. Early adoption is permitted. TEP is evaluating the impact of this update to its financial statements and disclosures.

RESTRICTED CASH

In November 2016, the FASB issued an accounting standard update that will require entities to show the changes in the total of cash, cash equivalents, and restricted cash or restricted cash equivalents in the statement of cash flows. As a result, entities will no longer present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. The standard is effective for annual and interim periods beginning January 1, 2018, and is to be applied using a retrospective approach. Early adoption is permitted. TEP is evaluating the impact of this update to its financial statements and disclosures.