(18) Segment Information Management views the Companys business primarily based on its underlying products and uses this basis to define its business segments. During the 2017 second quarter, the Company reorganized its business segments based on the internally-aligned segment leadership structure, which is how the Company monitors results and assesses performance. The Company now has three reportable segments: Individual Products &amp; Solutions (IPS), Retirement Plans and Corporate and Other. All prior period business segment results have been updated to conform to the current period presentation. The primary segment profitability measure that management uses is a financial measure called pre-tax operating earnings (loss), which is calculated by adjusting income before federal income taxes to exclude: (1) certain changes in variable annuity liabilities and net realized investment gains and losses, except for operating items, such as trading portfolio realized gains and losses, trading portfolio valuation changes and net realized gains and losses related to certain product hedges; (2) the adjustment to amortization of DAC related to certain changes in variable annuity liabilities and net realized investment gains and losses; and (3) net losses attributable to noncontrolling interest. The Company believes this financial measure enhances the understanding and comparability of its performance by highlighting its results from continuing operations and their underlying profit drivers. Individual Products and Solutions IPS offers the following products: individual deferred annuity contracts, immediate annuities, and various life insurance products. Individual deferred annuity contracts offered consist of deferred variable annuity contracts, deferred fixed annuity contracts and deferred fixed indexed annuity contracts. Deferred annuity contracts provide the customer with tax-deferred accumulation of savings and flexible payout options including lump sum, systematic withdrawal or a stream of payments for life. In addition, deferred variable annuity contracts provide the customer with access to a wide range of investment options and asset protection features. Deferred fixed annuity contracts offered by the Company generate a return for the customer at a specified interest rate fixed for prescribed periods, while deferred fixed indexed annuity contracts generate a return for the customer based on market performance with caps and floors. Immediate annuities differ from deferred annuities in that the initial premium is exchanged for a stream of income for a certain period and/or for the owners lifetime without future access to the original investment. The various life insurance products offered consist of individual variable universal life, COLI and BOLI products, traditional life insurance products, fixed universal life insurance products and indexed universal life insurance products. Life insurance products provide a death benefit and, for certain products, allow the customer to build cash value on a tax-advantaged basis. Retirement Plans The Retirement Plans segment is comprised of the private and public sector retirement plans businesses. The private sector business primarily includes Internal Revenue Code (IRC) Section 401 qualified plans funded through fixed and variable group annuity contracts issued through NLIC. The public sector business primarily includes IRC Section 457 (b) and Section 401(a) governmental plans, both in the form of full-service arrangements that provide plan administration along with fixed and variable group annuities, as well as administration-only business. Across the public and private sector business NIA managed account services are also available. The Retirement Plans segment also includes stable value wrap products and solutions. Corporate and Other The Corporate and Other segment includes the revenues and expenses associated with small business group life insurance and spread income on FHLB funding agreements. Additionally, certain non-operating changes in variable annuity liabilities and realized gains and losses, related amortization and other revenues and expenses not allocated to other segments are included within this segment. The following tables summarize the Companys business segment operating results for the years ended: (in millions) Individual Products and Solutions Retirement Plans Corporate and Other Total December 31, 2018 Revenues: Policy charges $ 2,623 126  $ 2,749 Premiums 658  37 695 Net investment income 1,655 835 185 2,675 Non-operating changes in variable annuity liabilities and net realized investment losses 1   (11 ) (11 ) Other revenues (expenses) 2 2  10 12 Total revenues $ 4,938 $ 961 $ 221 $ 6,120 Benefits and expenses: Interest credited to policyholder account values 3 $ 847 576 42 $ 1,465 Benefits and claims 4 1,387  97 1,484 Amortization of DAC 473 (4 ) (46 ) 423 Other expenses, net of deferrals 810 198 292 1,300 Total benefits and expenses $ 3,517 $ 770 $ 385 $ 4,672 Income (loss) before federal income taxes and noncontrolling interests $ 1,421 191 (164 ) $ 1,448 Less: certain non-operating changes in variable annuity liabilities and net realized investment losses 1   (11 ) Less: adjustment to amortization of DAC and other related expenses related to non-operating items above   48 Less: net loss attributable to noncontrolling interest   (168 ) Pre-tax operating earnings (loss) $ 1,421 $ 191 $ (33 ) $ 1,448 Assets as of year end $ 131,820 $ 33,933 $ 13,325 $ 179,078 1 Excluding operating items (trading portfolio realized gains and losses, trading portfolio valuation changes and net realized gains and losses related to certain product hedges). 2 Includes operating items (trading portfolio realized gains and losses, trading portfolio valuation changes). 3 Includes operating items (net realized gains and losses related to certain product hedges). 4 Excludes certain non-operating changes in variable annuity liabilities. (in millions) Individual Products and Solutions Retirement Plans Corporate and Other Total December 31, 2017 Revenues: Policy charges $ 2,428 $ 117 $  $ 2,545 Premiums 596  37 633 Net investment income 1,521 835 58 2,414 Non-operating changes in variable annuity liabilities and net realized investment losses 1   (318 ) (318 ) Other revenues 2 1  9 10 Total revenues $ 4,546 $ 952 $ (214 ) $ 5,284 Benefits and expenses: Interest credited to policyholder account values 3 $ 783 $ 557 $ 36 $ 1,376 Benefits and claims 4 1,395  27 1,422 Amortization of DAC 332 6 54 392 Other expenses, net of deferrals 741 194 258 1,193 Total benefits and expenses $ 3,251 $ 757 $ 375 $ 4,383 Income before federal income taxes and noncontrolling interests $ 1,295 $ 195 $ (589 ) $ 901 Less: certain non-operating changes in variable annuity liabilities and net realized investment (losses) 1   (318 ) Less: adjustment to amortization of DAC and other related expenses related to non-operating items above   (54 ) Less: net loss attributable to noncontrolling interest   (96 ) Pre-tax operating earnings (loss) $ 1,295 $ 195 $ (121 ) Assets as of year end $ 134,326 $ 35,520 $ 11,343 $ 181,189 1 Excluding operating items (trading portfolio realized gains and losses, trading portfolio valuation changes and net realized gains and losses related to certain product hedges). 2 Includes operating items (trading portfolio realized gains and losses, trading portfolio valuation changes). 3 Includes operating items (net realized gains and losses related to certain product hedges). 4 Excludes certain non-operating changes in variable annuity liabilities. (in millions) Individual Products and Solutions Retirement Plans Corporate and Other Total December 31, 2016 Revenues: Policy charges $ 2,254 $ 107 $  $ 2,361 Premiums 605  37 642 Net investment income 1,337 791 11 2,139 Non-operating changes in variable annuity liabilities and net realized investment losses 1   (299 ) (299 ) Other revenues 2   14 14 Total revenues $ 4,196 $ 898 $ (237 ) $ 4,857 Benefits and expenses: Interest credited to policyholder account values 3 $ 684 $ 531 $ 30 $ 1,245 Benefits and claims 4 1,245  32 1,277 Amortization of DAC 432 4 (3 ) 433 Other expenses, net of deferrals 654 181 163 998 Total benefits and expenses $ 3,015 $ 716 $ 222 $ 3,953 Income before federal income taxes and noncontrolling interests $ 1,181 $ 182 $ (459 ) $ 904 Less: certain non-operating changes in variable annuity liabilities and net realized investment gains 1   (299 ) Less: adjustment to amortization of DAC and other related expenses related to non-operating items above   6 Less: net loss attributable to noncontrolling interest   (91 ) Pre-tax operating earnings (loss) $ 1,181 $ 182 $ (75 ) Assets as of year end $ 113,062 $ 32,239 $ 10,337 $ 155,638 1 Excluding operating items (trading portfolio realized gains and losses, trading portfolio valuation changes and net realized gains and losses related to certain product hedges). 2 Includes operating items (trading portfolio realized gains and losses, trading portfolio valuation changes). 3 Includes operating items (net realized gains and losses related to certain product hedges). 4 Excludes certain non-operating changes in variable annuity liabilities.