Income Taxes	6 Months Ended
Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	4. Income Taxes Effective July 1, 2016 and due to the Merger with Emera, TEC is included in a consolidated U.S. federal income tax return with EUSHI and its subsidiaries. Prior to the Merger, TEC was included in the filing of a consolidated federal income tax return with TECO Energy and its subsidiaries. TEC’s income tax expense is based upon a separate return method, modified for the benefits-for-loss allocation in accordance with respective tax sharing agreements of TECO Energy and EUSHI. To the extent that TEC’s cash tax positions are settled differently than the amount reported as realized under the tax sharing agreement, the difference is accounted for as either a capital contribution or a distribution. The IRS concluded its examination of TECO Energy’s 2015 consolidated federal income tax return in March 2017 with no changes required. The U.S. federal statute of limitations remains open for the year 2013 and forward. The short tax year ending June 30, 2016 is currently under examination by the IRS under its Compliance Assurance Program (CAP). Due to the Merger with Emera, TECO Energy is only able to participate in the CAP through its short tax year ending June 30, 2016. TEC’s effective tax rates for the six months ended June 30, 2017 and 2016 were 38.53% and 35.94%, respectively. The increase in the six-month effective tax rate in 2017 versus the same period in 2016 is primarily due to lower AFUDC-equity and production deduction tax benefits. TEC’s effective tax rate for the six months ended June 30, 2017 differs from the statutory rate principally due to state income taxes. TEC’s effective tax rate for the six months ended June 30, 2016 differs from the statutory rate principally due to state income taxes offset by tax benefits related to AFUDC-equity and production deduction. As of June 30, 2017, the amount of unrecognized tax benefits was $7 million, all of which was recorded as a reduction of deferred income tax assets for tax credit carryforwards. TEC believes that the total unrecognized tax benefits will decrease within the next twelve months due to the expected audit examination of TECO Energy’s consolidated federal income tax return for the short tax year ending June 30, 2016. TEC had $7 million of unrecognized tax benefits at June 30, 2017, that, if recognized, would reduce TEC’s effective tax rate.

4. Income Taxes

Effective July 1, 2016 and due to the Merger with Emera, TEC is included in a consolidated U.S. federal income tax return with EUSHI and its subsidiaries. Prior to the Merger, TEC was included in the filing of a consolidated federal income tax return with TECO Energy and its subsidiaries. TEC’s income tax expense is based upon a separate return method, modified for the benefits-for-loss allocation in accordance with respective tax sharing agreements of TECO Energy and EUSHI. To the extent that TEC’s cash tax positions are settled differently than the amount reported as realized under the tax sharing agreement, the difference is accounted for as either a capital contribution or a distribution.

The IRS concluded its examination of TECO Energy’s 2015 consolidated federal income tax return in March 2017 with no changes required. The U.S. federal statute of limitations remains open for the year 2013 and forward. The short tax year ending June 30, 2016 is currently under examination by the IRS under its Compliance Assurance Program (CAP). Due to the Merger with Emera, TECO Energy is only able to participate in the CAP through its short tax year ending June 30, 2016.

TEC’s effective tax rates for the six months ended June 30, 2017 and 2016 were 38.53% and 35.94%, respectively. The increase in the six-month effective tax rate in 2017 versus the same period in 2016 is primarily due to lower AFUDC-equity and production deduction tax benefits. TEC’s effective tax rate for the six months ended June 30, 2017 differs from the statutory rate principally due to state income taxes. TEC’s effective tax rate for the six months ended June 30, 2016 differs from the statutory rate principally due to state income taxes offset by tax benefits related to AFUDC-equity and production deduction.

As of June 30, 2017, the amount of unrecognized tax benefits was $7 million, all of which was recorded as a reduction of deferred income tax assets for tax credit carryforwards. TEC believes that the total unrecognized tax benefits will decrease within the next twelve months due to the expected audit examination of TECO Energy’s consolidated federal income tax return for the short tax year ending June 30, 2016. TEC had $7 million of unrecognized tax benefits at June 30, 2017, that, if recognized, would reduce TEC’s effective tax rate.