consolidated other income ( expense ) items , net .
what was the average investment income ( loss ) net 2013 to 2015
interest expense interest expense increased in 2015 primarily due to an increase in our debt outstanding and $ 47 million of additional interest expense associated with the early redemption in june 2015 of our $ 750 million aggregate principal amount of 5.85% ( 5.85 % ) senior notes due november 2015 and our $ 1.0 billion aggregate principal amount of 5.90% ( 5.90 % ) senior notes due march 2016 . interest expense increased in 2014 primarily due to the effect of our interest rate derivative financial instruments . investment income ( loss ) , net the change in investment income ( loss ) , net in 2015 was primarily due to a $ 154 million gain related to the sale of our shares of arris group common stock in 2014 . the change in investment income ( loss ) , net in 2014 was primarily due to a $ 443 million gain related to the sale of our investment in clearwire corporation in 2013 . the components of investment income ( loss ) , net are presented in a table in note 7 to comcast 2019s consolidated financial statements . equity in net income ( losses ) of investees , net the change in equity in net income ( losses ) of investees , net in 2015 was primarily due to twcc holding corp . ( 201cthe weather channel 201d ) recording impairment charges related to goodwill . we recorded expenses of $ 333 million in 2015 that represent nbcuniversal 2019s proportionate share of these impairment charges . the change in 2015 was also due to an increase in our proportionate share of losses in hulu , llc ( 201chulu 201d ) , which were driven by hulu 2019s higher programming and marketing costs . in 2015 and 2014 , we recognized our pro- portionate share of losses of $ 106 million and $ 20 million , respectively , related to our investment in hulu . the change in equity in net income ( losses ) of investees , net in 2014 was primarily due to $ 142 million of total equity losses recorded in 2013 attributable to our investment in hulu . in july 2013 , we entered into an agreement to provide capital contributions totaling $ 247 million to hulu , which we had previously accounted for as a cost method investment . this represented an agreement to provide our first capital contribution to hulu since we acquired our interest in it as part of our acquisition of a controlling interest in nbcuniversal in 2011 ( the 201cnbcuniversal transaction 201d ) ; therefore , we began to apply the equity method of accounting for this investment . the change in the method of accounting for this investment required us to recognize our propor- tionate share of hulu 2019s accumulated losses from the date of the nbcuniversal transaction through july 2013 . other income ( expense ) , net other income ( expense ) , net for 2015 included gains of $ 335 million on the sales of a business and an invest- ment , $ 240 million recorded on the settlement of a contingent consideration liability with general electric company ( 201cge 201d ) related to the acquisition of nbcuniversal , and $ 43 million related to an equity method investment . these gains were partially offset by $ 236 million of expenses related to fair value adjustments to a contractual obligation . see note 11 to comcast 2019s consolidated financial statements for additional information on this contractual obligation . other income ( expense ) , net for 2014 included a $ 27 million favorable settlement of a contingency related to the at&t broadband transaction in 2002 , which was more than offset by $ 208 million of expenses related to 61 comcast 2015 annual report on form 10-k .