Financial report context:
uncertain tax positions the following is a reconciliation of the company 2019s beginning and ending amount of uncertain tax positions ( in millions ) : .

Financial table:
2018: balance at january 1; 2017: $ 280; column_3: $ 278
2018: additions based on tax positions related to the current year; 2017: 18; column_3: 25
2018: additions for tax positions of prior years; 2017: 10; column_3: 12
2018: reductions for tax positions of prior years; 2017: -24 ( 24 ); column_3: -26 ( 26 )
2018: settlements; 2017: 2014; column_3: -6 ( 6 )
2018: business combinations; 2017: 1; column_3: 2014
2018: lapse of statute of limitations; 2017: -6 ( 6 ); column_3: -7 ( 7 )
2018: foreign currency translation; 2017: 2014; column_3: 4
2018: balance at december 31; 2017: $ 279; column_3: $ 280

Additional report context:
the company 2019s liability for uncertain tax positions as of december 31 , 2018 , 2017 , and 2016 , includes $ 228 million , $ 219 million , and $ 240 million , respectively , related to amounts that would impact the effective tax rate if recognized . it is possible that the amount of unrecognized tax benefits may change in the next twelve months ; however , the company does not expect the change to have a significant impact on its consolidated statements of income or consolidated balance sheets . these changes may be the result of settlements of ongoing audits . at this time , an estimate of the range of the reasonably possible outcomes within the twelve months cannot be made . the company recognizes interest and penalties related to uncertain tax positions in its provision for income taxes . the company accrued potential interest and penalties of $ 22 million , $ 11 million , and $ 15 million in 2018 , 2017 , and 2016 , respectively . the company recorded a liability for interest and penalties of $ 77 million , $ 55 million , and $ 48 million as of december 31 , 2018 , 2017 , and 2016 , respectively . the company and its subsidiaries file income tax returns in their respective jurisdictions . the company has substantially concluded all u.s . federal income tax matters for years through 2007 . material u.s . state and local income tax jurisdiction examinations have been concluded for years through 2005 . the company has concluded income tax examinations in its primary non-u.s . jurisdictions through 2010 . 12 . shareholders 2019 equityq y distributable reserves as a company incorporated in england and wales , aon is required under u.k . law to have available 201cdistributable reserves 201d to make share repurchases or pay dividends to shareholders . distributable reserves may be created through the earnings of the u.k . parent company and , among other methods , through a reduction in share capital approved by the courts of england and wales . distributable reserves are not directly linked to a u.s . gaap reported amount ( e.g. , retained earnings ) . as of december 31 , 2018 and 2017 , the company had distributable reserves in excess of $ 2.2 billion and $ 1.2 billion , respectively . ordinary shares aon has a share repurchase program authorized by the company 2019s board of directors ( the 201crepurchase program 201d ) . the repurchase program was established in april 2012 with $ 5.0 billion in authorized repurchases , and was increased by $ 5.0 billion in authorized repurchases in each of november 2014 and february 2017 for a total of $ 15.0 billion in repurchase authorizations . under the repurchase program , class a ordinary shares may be repurchased through the open market or in privately negotiated transactions , from time to time , based on prevailing market conditions , and will be funded from available capital. .

Question: what is the decrease observed in the additions for tax positions of prior years , in millions?
Answer: 2