S- I/A Table of Contents FIRST DATA CORPORATION NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS (Continued) The primary components of assets and liabilities arc settlement-related accounts similar to those described in Note 4 "Settlement Assets and Obligations" of these consolidated financial statements. Scar ended Ittrember 31, On millions) 2014 2013 2012 Net operating revenues $1,357 $1.369 $1,278 Operating expenses 638 675 630 Operating income $ 719 $ 694 S 648 Net income $ 696 $ 664 $ 639 FDC equity earnings 220 188 158 The formation of a merchant alliance accounted for under the equity method of accounting generally involves the Company and/or a financial institution contributing merchant contracts to the alliance and a cash payment from one owner to the other to achieve the desired ownership percentages. The asset amounts reflected above arc owned by the alliances and other equity method investees and do not include any of such payments made by the Company. The amount by which the total of the Company's investments in affiliates exec= ed its proportionate share of the investees' net assets was approximately $1.1 billion and $1.2 billion as of December 31, 2014 and 2013, respectively. The non-goodwill portion of this amount is considered an identifiable intangible asset that is amortized. The estimated future amortization expense for these intangible assets as of December 31, 2014 is as follows: Year ended December 31, On millions) Amount 2015 $ 57 2016 51 2017 47 2018 29 2019 5 Thereafter These amounts assume that these alliances continue as they currently exist. Much of the difference between FDC's proportionate share of the invtatees' net income and FDC's equity earnings noted above relates to this amortization. Note 17: Supplemental Guarantor Condensed C'omolidating Financial Statements As described in Note 6 "Borrowings" of these consolidate) financial statements. FDC's 12.625% senior notta. 11.25% sen