income taxes american water and its subsidiaries participate in a consolidated federal income tax return for u.s . tax purposes . members of the consolidated group are charged with the amount of federal income tax expense determined as if they filed separate returns . certain income and expense items are accounted for in different time periods for financial reporting than for income tax reporting purposes . the company provides deferred income taxes on the difference between the tax basis of assets and liabilities and the amounts at which they are carried in the financial statements . these deferred income taxes are based on the enacted tax rates expected to be in effect when these temporary differences are projected to reverse . in addition , the regulated utility subsidiaries recognize regulatory assets and liabilities for the effect on revenues expected to be realized as the tax effects of temporary differences , previously flowed through to customers , reverse . investment tax credits have been deferred by the regulated utility subsidiaries and are being amortized to income over the average estimated service lives of the related assets . the company recognizes accrued interest and penalties related to tax positions as a component of income tax expense and accounts for sales tax collected from customers and remitted to taxing authorities on a net basis . see note 13 2014income taxes . allowance for funds used during construction afudc is a non-cash credit to income with a corresponding charge to utility plant that represents the cost of borrowed funds or a return on equity funds devoted to plant under construction . the regulated utility subsidiaries record afudc to the extent permitted by the pucs . the portion of afudc attributable to borrowed funds is shown as a reduction of interest , net in the accompanying consolidated statements of operations . any portion of afudc attributable to equity funds would be included in other income ( expenses ) in the accompanying consolidated statements of operations . afudc is summarized in the following table for the years ended december 31: .

Table: 2017 2016 2015 allowance for other funds used during construction $ 19 $ 15 $ 13 allowance for borrowed funds used during construction 8 6 8

environmental costs the company 2019s water and wastewater operations and the operations of its market-based businesses are subject to u.s . federal , state , local and foreign requirements relating to environmental protection , and as such , the company periodically becomes subject to environmental claims in the normal course of business . environmental expenditures that relate to current operations or provide a future benefit are expensed or capitalized as appropriate . remediation costs that relate to an existing condition caused by past operations are accrued , on an undiscounted basis , when it is probable that these costs will be incurred and can be reasonably estimated . a conservation agreement entered into by a subsidiary of the company with the national oceanic and atmospheric administration in 2010 and amended in 2017 required the company to , among other provisions , implement certain measures to protect the steelhead trout and its habitat in the carmel river watershed in the state of california . the company agreed to pay $ 1 million annually commencing in 2010 with the final payment being made in 2021 . remediation costs accrued amounted to $ 6 million and less than $ 1 million as of december 31 , 2017 and 2016 , respectively . derivative financial instruments the company uses derivative financial instruments for purposes of hedging exposures to fluctuations in interest rates . these derivative contracts are entered into for periods consistent with the related underlying .

Question: what was the combined amount of allowance for funds used in and funds borrowed in construction in 2016
Answer: 21
Calculation: add(15, const_6)
Explanation: the combined amount of allowance of funds used and borrowed in any years is the sum of the separate amounts