Seattle City Light 2016 ANNUAL REPORT | Audited Financial Statements 43 THE CITY OF SEATTLE—CITY LIGHT DEPARTMENT NOTES TO FINANCIAL STATEMENTS AS OF AND FOR THE YEARS ENDED DECEMBER 31, 2016 AND 2015 - 43 - ● Suburban infrastructure long-term receivables are underground electrical infrastructure costs for suburban jurisdictions, which are recovered through rates from customers within the respective jurisdictions for a period of approximately 25 years, as approved by the Seattle City Council. ● Long-term interfund receivable for expected recoveries related to environmental costs covered under GASB Statement No. 49, Accounting and Financial Reporting for Pollution Remediation Obligations (see Note 14 Environmental Liabilities). ● Puget Sound Energy interconnection and substation costs are being amortized to expense over 25 years. ● Studies, surveys, and investigations are reported as regulatory assets until such time they result in active projects, or when it is determined no assets will result, at which time they are expensed. ● Long-term customer loans receivable and the remaining components of other assets, are not amortized. Regulatory assets and other assets, net, at December 31, 2016 and 2015, consisted of the following: ($ in millions) 2016 2015 Regulatory assets: Conservation costs—net 252.4 $ 243.8 $ Endangered Species Act costs—net 1.9 2.0 Environmental costs 83.1 31.2 337.4 277.0 Other charges and assets—net: Suburban infrastructure long-term receivables 53.3 53.2 Long-term interfund receivable for environmental costs 3.0 4.1 Long-term customer notes receivable 0.3 0.7 Puget Sound Energy interconnection and substation 0.4 0.5 Studies, surveys, and investigations 2.8 2.8 Other (1.0) 1.2 58.8 62.5 Total Other Assets 396.2 $ 339.5 $ 8. DEFERRED OUTFLOWS OF RESOURCES Effective January 1, 2015, the Department adopted GASB Statement No. 68, Accounting and Financial Reporting for Pensions – an amendment of GASB Statement No. 27 and Statement No. 71, Pension Transition for Contributions Made Subsequent to the Measurement Date – an amendment of GASB Statement No. 68. GASB Statement Nos. 68 and 71 require that employer contributions made between the pension plan measurement date and the employer’s fiscal year end be recognized as deferred outflows of resources. Also to be recognized as deferred outflows of resources are losses resulting from differences between projected and actual earnings on plan investments, which are amortized over a closed five-year period, and losses related to differences between expected and actual experience with regard to economic