the aes corporation notes to consolidated financial statements 2014 ( continued ) december 31 , 2017 , 2016 , and 2015 the total amount of unrecognized tax benefits anticipated to result in a net decrease to unrecognized tax benefits within 12 months of december 31 , 2017 is estimated to be between $ 5 million and $ 15 million , primarily relating to statute of limitation lapses and tax exam settlements .the following is a reconciliation of the beginning and ending amounts of unrecognized tax benefits for the periods indicated ( in millions ) : .
[['december 31,', '2017', '2016', '2015'], ['balance at january 1', '$ 352', '$ 364', '$ 384'], ['additions for current year tax positions', '2014', '2', '2'], ['additions for tax positions of prior years', '2', '1', '12'], ['reductions for tax positions of prior years', '-5 ( 5 )', '-1 ( 1 )', '-7 ( 7 )'], ['effects of foreign currency translation', '2014', '2014', '-3 ( 3 )'], ['settlements', '2014', '-13 ( 13 )', '-17 ( 17 )'], ['lapse of statute of limitations', '-1 ( 1 )', '-1 ( 1 )', '-7 ( 7 )'], ['balance at december 31', '$ 348', '$ 352', '$ 364']]
the company and certain of its subsidiaries are currently under examination by the relevant taxing authorities for various tax years .the company regularly assesses the potential outcome of these examinations in each of the taxing jurisdictions when determining the adequacy of the amount of unrecognized tax benefit recorded .while it is often difficult to predict the final outcome or the timing of resolution of any particular uncertain tax position , we believe we have appropriately accrued for our uncertain tax benefits .however , audit outcomes and the timing of audit settlements and future events that would impact our previously recorded unrecognized tax benefits and the range of anticipated increases or decreases in unrecognized tax benefits are subject to significant uncertainty .it is possible that the ultimate outcome of current or future examinations may exceed our provision for current unrecognized tax benefits in amounts that could be material , but cannot be estimated as of december 31 , 2017 .our effective tax rate and net income in any given future period could therefore be materially impacted .21 .discontinued operations due to a portfolio evaluation in the first half of 2016 , management decided to pursue a strategic shift of its distribution companies in brazil , sul and eletropaulo , to reduce the company's exposure to the brazilian distribution market .eletropaulo 2014 in november 2017 , eletropaulo converted its preferred shares into ordinary shares and transitioned the listing of those shares into the novo mercado , which is a listing segment of the brazilian stock exchange with the highest standards of corporate governance .upon conversion of the preferred shares into ordinary shares , aes no longer controlled eletropaulo , but maintained significant influence over the business .as a result , the company deconsolidated eletropaulo .after deconsolidation , the company's 17% ( 17 % ) ownership interest is reflected as an equity method investment .the company recorded an after-tax loss on deconsolidation of $ 611 million , which primarily consisted of $ 455 million related to cumulative translation losses and $ 243 million related to pension losses reclassified from aocl .in december 2017 , all the remaining criteria were met for eletropaulo to qualify as a discontinued operation .therefore , its results of operations and financial position were reported as such in the consolidated financial statements for all periods presented .eletropaulo's pre-tax loss attributable to aes , including the loss on deconsolidation , for the years ended december 31 , 2017 and 2016 was $ 633 million and $ 192 million , respectively .eletropaulo's pre-tax income attributable to aes for the year ended december 31 , 2015 was $ 73 million .prior to its classification as discontinued operations , eletropaulo was reported in the brazil sbu reportable segment .sul 2014 the company executed an agreement for the sale of sul , a wholly-owned subsidiary , in june 2016 .the results of operations and financial position of sul are reported as discontinued operations in the consolidated financial statements for all periods presented .upon meeting the held-for-sale criteria , the company recognized an after-tax loss of $ 382 million comprised of a pre-tax impairment charge of $ 783 million , offset by a tax benefit of $ 266 million related to the impairment of the sul long lived assets and a tax benefit of $ 135 million for deferred taxes related to the investment in sul .prior to the impairment charge , the carrying value of the sul asset group of $ 1.6 billion was greater than its approximate fair value less costs to sell .however , the impairment charge was limited to the carrying value of the long lived assets of the sul disposal group .on october 31 , 2016 , the company completed the sale of sul and received final proceeds less costs to sell of $ 484 million , excluding contingent consideration .upon disposal of sul , the company incurred an additional after-tax .

Question: what was the net change in millions in unrecognized tax benefits from 2015 to 2016?
Answer: -12