Regulatory assets and liabilities recorded in the balance sheet are summarized in the table below:



($ in millions)	Remaining Recovery Period (years)	September 30, 2018		December 31, 2017
Regulatory Assets
Pension and Other Postretirement Benefits	Various	$	121	$	126
Early Generation Retirement Costs ⁽¹⁾	Various	74		84
Income Taxes Recoverable through Future Rates	Various	43		40
Derivatives	3	42		18
Final Mine Reclamation and Retiree Healthcare Costs ⁽²⁾	19	33		31
Lost Fixed Cost Recovery	2	32		29
Property Tax Deferrals	1	25		24
Springerville Unit 1 Leasehold Improvements⁽³⁾	5	12		14
Other Regulatory Assets	Various	22		22
Total Regulatory Assets		404		388
Less Current Portion	1	110		94
Total Non-Current Regulatory Assets		$	294	$	294



Regulatory Liabilities
Income Taxes Payable through Future Rates ⁽⁴⁾	Various	$	346	$	353
Net Cost of Removal ⁽⁵⁾	Various	169		180
Renewable Energy Standard	Various	52		44
Purchased Power and Fuel Adjustment Clause	1	20		9
Deferred Investment Tax Credits	Various	8		14
Other Regulatory Liabilities	Various	9		5
Total Regulatory Liabilities		604		605
Less Current Portion	1	110		89
Total Non-Current Regulatory Liabilities		$	494	$	516


⁽¹⁾	Includes the net book value and other related costs of Navajo Generating Station (Navajo) and H. Wilson Sundt Generating Station (Sundt) Units 1 and 2 reclassified from Utility Plant, Net on the Condensed Consolidated Balance Sheets due to the planned early retirement of the facilities. Navajo and Sundt Units 1 and 2 are being fully recovered in base rates using various useful lives through 2030.


⁽²⁾	Represents costs associated with TEP’s jointly-owned facilities at San Juan, Four Corners Generating Station (Four Corners), and Navajo. TEP recognizes these costs at future value and is permitted to recover these costs on a pay-as-you-go basis through the PPFAC mechanism. The majority of final mine reclamation costs are expected to occur through 2037.


⁽³⁾	Represents investments TEP made, which were previously recorded in Plant in Service on the Condensed Consolidated Balance Sheets, to ensure that the facilities continued to provide service to TEP's customers. TEP received ACC authorization to recover leasehold improvement costs at Springerville Unit 1 over a 10-year amortization period.

⁽⁴⁾

Includes balances related to EDIT as a result of the revaluation of deferred income taxes in 2017 due to the TCJA. TEP is amortizing the EDIT balances in accordance with applicable federal income tax laws, which require the amortization of a majority of the balance over the remaining life of the related asset. In April 2018, the ACC Refund Order was approved requiring TEP to return EDIT amortization of the ACC-jurisdictional assets with customers. See Note 11 for additional information regarding the TCJA.


⁽⁵⁾	Represents an estimate of the future cost of retirement net of salvage value. These are amounts collected through revenue for transmission, distribution, and generation plant and general and intangible plant which are not yet expended.