Investments | 6. Investments Fixed Maturity Securities Available-for-Sale Fixed Maturity Securities Available-for-Sale by Sector The following table presents the fixed maturity securities AFS by sector. Redeemable preferred stock is reported within U.S. corporate and foreign corporate fixed maturity securities. Included within fixed maturity securities AFS are structured securities including residential mortgage-backed securities (“RMBS”), asset-backed securities (“ABS”) and commercial mortgage-backed securities (“CMBS”) (collectively, “Structured Securities”). June 30, 2018 December 31, 2017 Amortized Gross Unrealized Estimated Amortized Gross Unrealized Estimated Temporary OTTI Temporary OTTI (In millions) Fixed maturity securities: U.S. corporate $ 81,382 $ 4,233 $ 1,589 $ — $ 84,026 $ 76,005 $ 7,007 $ 351 $ — $ 82,661 Foreign government 56,106 6,082 506 — 61,682 55,351 6,495 312 — 61,534 Foreign corporate 52,930 2,780 1,433 — 54,277 52,409 3,836 676 — 55,569 U.S. government and agency 42,701 3,229 543 — 45,387 43,446 4,227 279 — 47,394 RMBS 27,390 976 556 (35 ) 27,845 27,846 1,145 233 (42 ) 28,800 State and political subdivision 10,683 1,395 52 — 12,026 10,752 1,717 13 1 12,455 ABS 12,818 85 36 1 12,866 12,213 116 39 (1 ) 12,291 CMBS 8,247 92 117 — 8,222 8,047 222 42 — 8,227 Total fixed maturity securities $ 292,257 $ 18,872 $ 4,832 $ (34 ) $ 306,331 $ 286,069 $ 24,765 $ 1,945 $ (42 ) $ 308,931 __________________ (1) Noncredit OTTI losses included in AOCI in an unrealized gain position are due to increases in estimated fair value subsequent to initial recognition of noncredit losses on such securities. See also “— Net Unrealized Investment Gains (Losses).” The Company held non-income producing fixed maturity securities with an estimated fair value of $24 million and $6 million , and unrealized gains (losses) of ($1) million and ($4) million , at June 30, 2018 and December 31, 2017 , respectively. Maturities of Fixed Maturity Securities The amortized cost and estimated fair value of fixed maturity securities, by contractual maturity date, were as follows at June 30, 2018 : Due in One Due After Due After Five Years Through Ten Years Due After Ten Years Structured Securities Total Fixed Maturity Securities (In millions) Amortized cost $ 13,437 $ 59,285 $ 61,369 $ 109,711 $ 48,455 $ 292,257 Estimated fair value $ 13,456 $ 60,971 $ 63,077 $ 119,894 $ 48,933 $ 306,331 Actual maturities may differ from contractual maturities due to the exercise of call or prepayment options. Fixed maturity securities not due at a single maturity date have been presented in the year of final contractual maturity. Structured Securities are shown separately, as they are not due at a single maturity. Continuous Gross Unrealized Losses for Fixed Maturity Securities AFS by Sector The following table presents the estimated fair value and gross unrealized losses of fixed maturity securities AFS in an unrealized loss position, aggregated by sector and by length of time that the securities have been in a continuous unrealized loss position at: June 30, 2018 December 31, 2017 Less than 12 Months Equal to or Greater than 12 Months Less than 12 Months Equal to or Greater than 12 Months Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses (Dollars in millions) Fixed maturity securities: U.S. corporate $ 29,888 $ 1,145 $ 4,227 $ 444 $ 5,604 $ 92 $ 4,115 $ 259 Foreign government 5,007 258 2,960 248 4,234 83 3,251 229 Foreign corporate 14,309 865 4,676 568 4,422 99 6,802 577 U.S. government and agency 18,165 217 3,300 326 18,273 93 3,560 186 RMBS 11,604 307 3,537 214 6,359 50 4,159 141 State and political subdivision 1,064 31 299 21 182 2 346 12 ABS 4,588 17 445 20 1,695 7 729 31 CMBS 4,276 74 421 43 1,174 9 413 33 Total fixed maturity securities $ 88,901 $ 2,914 $ 19,865 $ 1,884 $ 41,943 $ 435 $ 23,375 $ 1,468 Total number of securities in an unrealized loss position 6,572 1,881 2,598 1,955 Evaluation of AFS Securities for OTTI and Evaluating Temporarily Impaired AFS Securities As described more fully in Notes 1 and 8 of the Notes to the Consolidated Financial Statements included in the 2017 Annual Report, the Company performs a regular evaluation of all investment classes for impairment, including fixed maturity securities and perpetual hybrid securities, in accordance with its impairment policy, in order to evaluate whether such investments are other-than-temporarily impaired. Current Period Evaluation Based on the Company’s current evaluation of its AFS securities in an unrealized loss position in accordance with its impairment policy, and the Company’s current intentions and assessments (as applicable to the type of security) about holding, selling and any requirements to sell these securities, the Company concluded that these securities were not other-than-temporarily impaired at June 30, 2018 . Future OTTI will depend primarily on economic fundamentals, issuer performance (including changes in the present value of future cash flows expected to be collected), changes in credit ratings, collateral valuation, interest rates and credit spreads. If economic fundamentals deteriorate or if there are adverse changes in the above factors, OTTI may be incurred in upcoming periods. Gross unrealized losses on fixed maturity securities increased $2.9 billion during the six months ended June 30, 2018 to $4.8 billion . The increase in gross unrealized losses for the six months ended June 30, 2018 was primarily attributable to widening credit spreads, increases in interest rates and to a lesser extent, the impact of weakening foreign currencies on non-functional currency denominated fixed maturity securities. At June 30, 2018 , $67 million of the total $4.8 billion of gross unrealized losses were from 32 fixed maturity securities with an unrealized loss position of 20% or more of amortized cost for six months or greater. Investment Grade Fixed Maturity Securities Of the $67 million of gross unrealized losses on fixed maturity securities with an unrealized loss of 20% or more of amortized cost for six months or greater, $15 million , or 22% , were related to gross unrealized losses on 10 investment grade fixed maturity securities. Unrealized losses on investment grade fixed maturity securities are principally related to widening credit spreads since purchase and, with respect to fixed-rate fixed maturity securities, rising interest rates since purchase. Below Investment Grade Fixed Maturity Securities Of the $67 million of gross unrealized losses on fixed maturity securities with an unrealized loss of 20% or more of amortized cost for six months or greater, $52 million , or 78% , were related to gross unrealized losses on 22 below investment grade fixed maturity securities. Unrealized losses on below investment grade fixed maturity securities are principally related to U.S. and foreign corporate securities (primarily industrial and utility securities) and CMBS and are the result of significantly wider credit spreads resulting from higher risk premiums since purchase, largely due to economic and market uncertainty. Management evaluates U.S. and foreign corporate securities based on factors such as expected cash flows and the financial condition and near-term and long-term prospects of the issuers and evaluates CMBS based on actual and projected cash flows after considering the quality of underlying collateral, expected prepayment speeds, current and forecasted loss severity, the payment terms of the underlying assets backing a particular security and the payment priority within the tranche structure of the security. Equity Securities Equity securities are summarized as follows at: June 30, 2018 December 31, 2017 Estimated Fair Value % of Total Estimated Fair Value % of Total (Dollars in millions) Equity securities: Common stock $ 1,062 71.6 % $ 2,035 81.0 % Non-redeemable preferred stock 421 28.4 478 19.0 Total equity securities $ 1,483 100.0 % $ 2,513 100.0 % In connection with the adoption of new guidance related to the recognition and measurement of financial instruments (see Note 1 ), effective January 1, 2018, the Company has reclassified its investment in common stock in regional banks of the Federal Home Loan Bank (“FHLB”) system from equity securities to other invested assets. These investments are carried at redemption value and are considered restricted investments until redeemed by the respective FHLB regional banks. The carrying value of these investments at December 31, 2017 was $791 million . Unit-linked and FVO Securities Unit-linked and FVO Securities are investments for which the FVO has been elected, or are otherwise required to be carried at estimated fair value, and include: • contractholder-directed investments supporting unit-linked variable annuity type liabilities (“Unit-linked investments”) which do not qualify for presentation and reporting as separate account summary total assets and liabilities. These investments are primarily equity securities (including mutual funds) and, to a lesser extent, fixed maturity securities, short-term investments and cash and cash equivalents. The investment returns on these investments inure to contractholders and are offset by a corresponding change in policyholder account balances through interest credited to policyholder account balances; • fixed maturity and equity securities held-for-investment by the general account to support asset and liability management strategies for certain insurance products and investments in certain separate accounts; and • securities held by consolidated securitization entities. At December 31, 2017, Unit-linked and FVO Securities also included FVO Brighthouse Common Stock (see Note 3 ). Mortgage Loans Mortgage Loans by Portfolio Segment Mortgage loans are summarized as follows at: June 30, 2018 December 31, 2017 Carrying Value % of Carrying Value % of (Dollars in millions) Mortgage loans: Commercial $ 46,075 65.0 % $ 44,375 64.6 % Agricultural 13,293 18.8 13,014 18.9 Residential 11,404 16.1 11,136 16.2 Subtotal (1) 70,772 99.9 68,525 99.7 Valuation allowances (325 ) (0.5 ) (314 ) (0.5 ) Subtotal mortgage loans, net 70,447 99.4 68,211 99.2 Residential — FVO 405 0.6 520 0.8 Total mortgage loans, net $ 70,852 100.0 % $ 68,731 100.0 % __________________ (1) Purchases of mortgage loans, primarily residential mortgage loans, were $666 million and $973 million for the three months and six months ended June 30, 2018 , respectively, and $742 million and $1.5 billion for the three months and six months ended June 30, 2017 , respectively. Information on commercial, agricultural and residential mortgage loans is presented in the tables below. Information on residential mortgage loans — FVO is presented in Note 8 . The Company elects the FVO for certain residential mortgage loans that are managed on a total return basis. The carrying value of foreclosed mortgage loans included in real estate and real estate joint ventures was $45 million and $48 million at June 30, 2018 and December 31, 2017, respectively. Mortgage Loans, Valuation Allowance and Impaired Loans by Portfolio Segment Mortgage loans by portfolio segment, by method of evaluation of credit loss, impaired mortgage loans including those modified in a troubled debt restructuring, and the related valuation allowances, were as follows at: Evaluated Individually for Credit Losses Evaluated Collectively for Credit Losses Impaired Loans Impaired Loans with a Valuation Allowance Impaired Loans without a Valuation Allowance Unpaid Principal Balance Recorded Investment Valuation Unpaid Principal Balance Recorded Recorded Valuation Carrying (In millions) June 30, 2018 Commercial $ — $ — $ — $ — $ — $ 46,075 $ 227 $ — Agricultural 13 13 2 112 111 13,169 39 122 Residential — — — 401 362 11,042 57 362 Total $ 13 $ 13 $ 2 $ 513 $ 473 $ 70,286 $ 323 $ 484 December 31, 2017 Commercial $ — $ — $ — $ — $ — $ 44,375 $ 214 $ — Agricultural 22 21 2 27 27 12,966 39 46 Residential — — — 358 324 10,812 59 324 Total $ 22 $ 21 $ 2 $ 385 $ 351 $ 68,153 $ 312 $ 370 The average recorded investment for impaired commercial, agricultural and residential mortgage loans was $0 , $122 million and $351 million , respectively, for the three months ended June 30, 2018 ; and $0 , $97 million and $342 million , respectively, for the six months ended June 30, 2018 ; The average recorded investment for impaired commercial, agricultural and residential mortgage loans was $6 million , $13 million and $278 million , respectively, for the three months ended June 30, 2017 ; and $8 million , $21 million and $266 million , respectively, for the six months ended June 30, 2017 . Valuation Allowance Rollforward by Portfolio Segment The changes in the valuation allowance, by portfolio segment, were as follows: Six Months 2018 2017 Commercial Agricultural Residential Total Commercial Agricultural Residential Total (In millions) Balance, beginning of period $ 214 $ 41 $ 59 $ 314 $ 202 $ 39 $ 63 $ 304 Provision (release) 13 — 2 15 6 — 9 15 Charge-offs, net of recoveries — — (4 ) (4 ) — — (7 ) (7 ) Balance, end of period $ 227 $ 41 $ 57 $ 325 $ 208 $ 39 $ 65 $ 312 Credit Quality of Commercial Mortgage Loans The credit quality of commercial mortgage loans was as follows at: Recorded Investment Estimated % of Total Debt Service Coverage Ratios % of Total > 1.20x 1.00x - 1.20x < 1.00x Total (Dollars in millions) June 30, 2018 Loan-to-value ratios: Less than 65% $ 39,229 $ 691 $ 202 $ 40,122 87.1 % $ 40,488 87.3 % 65% to 75% 3,931 264 433 4,628 10.0 4,628 10.0 76% to 80% 405 210 56 671 1.5 638 1.4 Greater than 80% 478 176 — 654 1.4 618 1.3 Total $ 44,043 $ 1,341 $ 691 $ 46,075 100.0 % $ 46,372 100.0 % December 31, 2017 Loan-to-value ratios: Less than 65% $ 37,073 $ 1,483 $ 201 $ 38,757 87.4 % $ 39,528 87.7 % 65% to 75% 4,183 98 119 4,400 9.9 4,408 9.8 76% to 80% 235 210 57 502 1.1 476 1.0 Greater than 80% 401 168 147 716 1.6 672 1.5 Total $ 41,892 $ 1,959 $ 524 $ 44,375 100.0 % $ 45,084 100.0 % Credit Quality of Agricultural Mortgage Loans The credit quality of agricultural mortgage loans was as follows at: June 30, 2018 December 31, 2017 Recorded % of Recorded % of (Dollars in millions) Loan-to-value ratios: Less than 65% $ 12,576 94.6 % $ 12,347 94.9 % 65% to 75% 676 5.1 618 4.7 76% to 80% 32 0.2 40 0.3 Greater than 80% 9 0.1 9 0.1 Total $ 13,293 100.0 % $ 13,014 100.0 % The estimated fair value of agricultural mortgage loans was $13.2 billion and $13.1 billion at June 30, 2018 and December 31, 2017 , respectively. Credit Quality of Residential Mortgage Loans The credit quality of residential mortgage loans was as follows at: June 30, 2018 December 31, 2017 Recorded % of Recorded % of (Dollars in millions) Performance indicators: Performing $ 10,945 96.0 % $ 10,622 95.4 % Nonperforming 459 4.0 514 4.6 Total $ 11,404 100.0 % $ 11,136 100.0 % The estimated fair value of residential mortgage loans was $11.7 billion and $11.6 billion at June 30, 2018 and December 31, 2017 , respectively. Past Due and Nonaccrual Mortgage Loans The Company has a high quality, well performing mortgage loan portfolio, with 99% of all mortgage loans classified as performing at both June 30, 2018 and December 31, 2017 . The Company defines delinquency consistent with industry practice, when mortgage loans are past due as follows: commercial and residential mortgage loans — 60 days and agricultural mortgage loans — 90 days. The past due and nonaccrual mortgage loans at recorded investment, prior to valuation allowances, by portfolio segment, were as follows at: Past Due Greater than 90 Days Past Due and Still Accruing Interest Nonaccrual June 30, 2018 December 31, 2017 June 30, 2018 December 31, 2017 June 30, 2018 December 31, 2017 (In millions) Commercial $ 1 $ — $ — $ — $ 176 $ — Agricultural 233 134 136 125 107 36 Residential 459 514 31 33 428 481 Total $ 693 $ 648 $ 167 $ 158 $ 711 $ 517 Cash Equivalents The carrying value of cash equivalents, which includes securities and other investments with an original or remaining maturity of three months or less at the time of purchase, was $9.4 billion and $6.2 billion at June 30, 2018 and December 31, 2017 , respectively. Net Unrealized Investment Gains (Losses) Unrealized investment gains (losses) on fixed maturity securities AFS and equity securities and the effect on DAC, VOBA, deferred sales inducements (“DSI”), future policy benefits and the policyholder dividend obligation, that would result from the realization of the unrealized gains (losses), are included in net unrealized investment gains (losses) in AOCI. The components of net unrealized investment gains (losses), included in AOCI, were as follows: June 30, 2018 December 31, 2017 (In millions) Fixed maturity securities $ 13,918 $ 22,645 Fixed maturity securities with noncredit OTTI losses included in AOCI 34 41 Total fixed maturity securities 13,952 22,686 Equity securities — 421 Derivatives 1,547 1,453 Other 112 46 Subtotal 15,611 24,606 Amounts allocated from: Future policy benefits (132 ) (77 ) DAC, VOBA and DSI (1,156 ) (1,768 ) Policyholder dividend obligation (792 ) (2,121 ) Subtotal (2,080 ) (3,966 ) Deferred income tax benefit (expense) related to noncredit OTTI losses recognized in AOCI (5 ) (12 ) Deferred income tax benefit (expense) (3,814 ) (6,958 ) Net unrealized investment gains (losses) 9,712 13,670 Net unrealized investment gains (losses) attributable to noncontrolling interests (9 ) (8 ) Net unrealized investment gains (losses) attributable to MetLife, Inc. $ 9,703 $ 13,662 The changes in net unrealized investment gains (losses) were as follows: Six Months (In millions) Balance, beginning of period $ 13,662 Cumulative effects of changes in accounting principles, net of income tax (Note 1) 1,258 Fixed maturity securities on which noncredit OTTI losses have been recognized (7 ) Unrealized investment gains (losses) during the period (8,563 ) Unrealized investment gains (losses) relating to: Future policy benefits (55 ) DAC, VOBA and DSI 612 Policyholder dividend obligation 1,329 Deferred income tax benefit (expense) related to noncredit OTTI losses recognized in AOCI 7 Deferred income tax benefit (expense) 1,461 Net unrealized investment gains (losses) 9,704 Net unrealized investment gains (losses) attributable to noncontrolling interests (1 ) Balance, end of period $ 9,703 Change in net unrealized investment gains (losses) $ (3,958 ) Change in net unrealized investment gains (losses) attributable to noncontrolling interests (1 ) Change in net unrealized investment gains (losses) attributable to MetLife, Inc. $ (3,959 ) Concentrations of Credit Risk Investments in any counterparty that were greater than 10% of the Company’s equity, other than the U.S. government and its agencies, were in fixed income securities of the Japanese government and its agencies with an estimated fair value of $29.7 billion and $27.5 billion at June 30, 2018 and December 31, 2017 , respectively, and in fixed income securities of the South Korean government and its agencies with an estimated fair value of $6.4 billion and $6.5 billion at June 30, 2018 and December 31, 2017 , respectively. Securities Lending Elements of the Company’s securities lending program are presented below at: June 30, 2018 December 31, 2017 (In millions) Securities on loan: (1) Amortized cost $ 18,052 $ 17,801 Estimated fair value $ 18,846 $ 19,028 Cash collateral received from counterparties (2) $ 19,244 $ 19,417 Security collateral received from counterparties (3) $ 47 $ 19 Reinvestment portfolio — estimated fair value $ 19,374 $ 19,508 __________________ (1) Included within fixed maturity securities and cash equivalents. (2) Included within payables for collateral under securities loaned and other transactions. (3) Security collateral received from counterparties may not be sold or re-pledged, unless the counterparty is in default, and is not reflected on the interim condensed consolidated financial statements. The cash collateral liability by loaned security type and remaining tenor of the agreements was as follows at: June 30, 2018 December 31, 2017 Remaining Tenor of Securities Lending Agreements Remaining Tenor of Securities Lending Agreements Open (1) 1 Month or Less Over 1 to 6 Months Total Open (1) 1 Month or Less Over 1 to 6 Months Total (In millions) Cash collateral liability by loaned security type: U.S. government and agency $ 4,042 $ 4,274 $ 9,891 $ 18,207 $ 3,753 $ 6,031 $ 8,607 $ 18,391 Foreign government — 245 717 962 — 192 834 1,026 Agency RMBS — 75 — 75 — — — — Total $ 4,042 $ 4,594 $ 10,608 $ 19,244 $ 3,753 $ 6,223 $ 9,441 $ 19,417 __________________ (1) The related loaned security could be returned to the Company on the next business day which would require the Company to immediately return the cash collateral. If the Company is required to return significant amounts of cash collateral on short notice and is forced to sell securities to meet the return obligation, it may have difficulty selling such collateral that is invested in securities in a timely manner, be forced to sell securities in a volatile or illiquid market for less than what otherwise would have been realized under normal market conditions, or both. The estimated fair value of the securities on loan related to the cash collateral on open at June 30, 2018 was $4.0 billion , all of which were U.S. government and agency securities which, if put back to the Company, could be immediately sold to satisfy the cash requirement. The reinvestment portfolio acquired with the cash collateral consisted principally of fixed maturity securities (including agency RMBS, U.S. government and agency securities, and ABS), cash equivalents and short-term investments, with 62% invested in agency RMBS, U.S. government and agency securities, cash equivalents, short-term investments or held in cash. If the securities on loan or the reinvestment portfolio become less liquid, the Company has the liquidity resources of most of its general account available to meet any potential cash demands when securities on loan are put back to the Company. Repurchase Agreements Elements of the Company’s short-term repurchase agreements are presented below at: June 30, 2018 December 31, 2017 (In millions) Securities on loan: (1) Amortized cost $ 2,519 $ 994 Estimated fair value $ 2,622 $ 1,141 Cash collateral received from counterparties (2) $ 2,560 $ 1,102 Reinvestment portfolio — estimated fair value $ 2,568 $ 1,102 __________________ (1) Included within fixed maturity securities, cash equivalents and short-term investments. (2) Included within payables for collateral under securities loaned and other transactions and other liabilities. The cash collateral liability by loaned security type and remaining tenor of the agreements was as follows at: June 30, 2018 December 31, 2017 Remaining Tenor of Repurchase Agreements Remaining Tenor of Repurchase Agreements 1 Month or Less Over 1 to 6 Months Total 1 Month or Less Over 1 to 6 Months Total (In millions) Cash collateral liability by loaned security type: U.S. government and agency $ 2,465 $ — $ 2,465 $ 1,005 $ — $ 1,005 All other corporate and government 44 51 95 44 53 97 Total $ 2,509 $ 51 $ 2,560 $ 1,049 $ 53 $ 1,102 The reinvestment portfolio acquired with the cash collateral consisted principally of fixed maturity securities (including U.S. government and agency securities, agency RMBS, ABS and U.S. corporate securities) and cash equivalents, with 65% invested in U.S. government and agency securities, agency RMBS, cash equivalents, short-term investments, or held in cash. If the securities on loan or the reinvestment portfolio become less liquid, the Company has the liquidity resources of most of its general account available to meet any potential cash demands when securities on loan are put back to the Company. FHLB of Boston Advance Agreements At June 30, 2018 and December 31, 2017 , a subsidiary of the Company had pledged fixed maturity securities with an estimated fair value of $1.3 billion and $564 million , respectively, as collateral and received $800 million and $300 million , respectively, in cash advances under short-term advance agreements with the FHLB of Boston. The liability to return the cash advances is included within payables for collateral under securities loaned and other transactions. The estimated fair value of the reinvestment portfolio acquired with the cash advances was $806 million and $300 million at June 30, 2018 and December 31, 2017 , respectively, and consisted primarily of U.S. government and agency fixed maturity securities and Structured Securities. The subsidiary is permitted to withdraw any portion of the pledged collateral over the minimum collateral requirement at any time, other than in the event of a default by the subsidiary. The cash advance liability by loaned security type and remaining tenor of the agreements was as follows at: June 30, 2018 December 31, 2017 Remaining Tenor of Advance Agreements Remaining Tenor of Advance Agreements 1 Month or Less Over 1 to 6 Months 6 Months to 1 Year Total 1 Month or Less Over 1 to 6 Months 6 Months to 1 Year Total (In millions) Cash advance liability by loaned security type: State and political subdivision $ 100 $ 625 $ 75 $ 800 $ — $ 300 $ — $ 300 Invested Assets on Deposit, Held in Trust and Pledged as Collateral Invested assets on deposit, held in trust and pledged as collateral are presented below at estimated fair value for all asset classes, except mortgage loans, which are presented at carrying value, at: June 30, 2018 December 31, 2017 (In millions) Invested assets on deposit (regulatory deposits) $ 1,804 $ 1,879 Invested assets held in trust (collateral financing arrangement and reinsurance agreements) 3,100 2,490 Invested assets pledged as collateral 24,808 24,174 Total invested assets on deposit, held in trust and pledged as collateral $ 29,712 $ 28,543 The Company has pledged invested assets in connection with various agreements and transactions, including funding agreements (see Note 4 of the Notes to the Consolidated Financial Statements included in the 2017 Annual Report) and derivative transactions (see Note 7 ). Amounts in the table above include invested assets and cash and cash equivalents. See “— Securities Lending” and “— Repurchase Agreements” for information regarding securities on loan, Note 5 for information regarding investments designated to the closed block and “— Equity Securities” for information on common stock holdings in regional banks of the FHLB system, which are considered restricted investments. Variable Interest Entities The Company has invested in legal entities that are VIEs. In certain instances, the Company holds both the power to direct the most significant activities of the entity, as well as an economic interest in the entity and, as such, is deemed to be the primary beneficiary or consolidator of the entity. The determination of the VIE’s primary beneficiary requires an evaluation of the contractual and implied rights and obligations associated with each party’s relationship with or involvement in the entity, an estimate of the entity’s expected losses and expected residual returns and the allocation of such estimates to each party involved in the entity. Consolidated VIEs Creditors or beneficial interest holders of VIEs where the Company is the primary beneficiary have no recourse to the general credit of the Company, as the Company’s obligation to the VIEs is limited to the amount of its committed investment. The following table presents the total assets and total liabilities relating to investment-related VIEs for which the Company has concluded that it is the primary beneficiary and which are consolidated at: June 30, 2018 December 31, 2017 Total Total Total Total (In millions) Renewable energy partnership (1) $ 109 $ — $ 116 $ 3 Investment fund (2) 333 1 — — Other investments 31 5 32 6 Total $ 473 $ 6 $ 148 $ 9 __________________ (1) Assets of the renewable energy partnership primarily consisted of other invested assets. (2) Assets of the investment fund primarily consisted of other invested assets. Unconsolidated VIEs The carrying amount and maximum exposure to loss relating to VIEs in which the Company holds a significant variable interest but is not the primary beneficiary and which have not been consolidated were as follows at: June 30, 2018 December 31, 2017 Carrying Maximum Carrying Maximum (In millions) Fixed maturity securities AFS: Structured Securities (2) $ 46,531 $ 46,531 $ 47,614 $ 47,614 U.S. and foreign corporate 1,281 1,281 1,560 1,560 Other limited partnership interests 5,088 9,269 4,834 8,543 Other invested assets 1,866 2,080 2,291 2,625 Other investments 37 41 82 87 Total $ 54,803 $ 59,202 $ 56,381 $ 60,429 __________________ (1) The maximum exposure to loss relating to fixed maturity securities AFS is equal to their carrying amounts or the carrying amounts of retained interests. The maximum exposure to loss relating to other limited partnership interests is equal to the carrying amounts plus any unfunded commitments. For certain of its investments in other invested assets, the Company’s return is in the form of income tax credits which are guaranteed by creditworthy third parties. For such investments, the maximum exposure to loss is equal to the carrying amounts plus any unfunded commitments, reduced by income tax credits guaranteed by third parties of $107 million and $117 million at June 30, 2018 and December 31, 2017 , respectively. Such a maximum loss would be expected to occur only upon bankruptcy of the issuer or investee. (2) For these variable interests, the Company’s involvement is limited to that of a passive investor in mortgage-backed or asset-backed securities issued by trusts that do not have substantial equity. As described in Note 15 , the Company makes commitments to fund partnership investments in the normal course of business. Excluding these commitments, the Company did not provide financial or other support to investees designated as VIEs during both the six months ended June 30, 2018 and 2017 . Net Investment Income The components of net investment income were as follows: Three Months Six Months 2018 2017 2018 2017 (In millions) Investment income: Fixed maturity securities $ 3,014 $ 2,839 $ 5,910 $ 5,664 Equity securities 15 31 31 62 FVO Securities (1) 8 16 14 45 Mortgage loans 815 758 1,607 1,494 Policy loans 127 129 251 256 Real estate and real estate joint ventures 195 169 363 322 Other limited partnership interests 120 194 327 434 Cash, cash equivalents and short-term investments 95 56 167 107 Operating joint ventures 19 5 32 7 Other 94 53 200 125 Subtotal 4,502 4,250 8,902 8,516 Less: Investment expenses 315 271 617 532 Subtotal, net 4,187 3,979 8,285 7,984 Unit-linked investments (1) 286 214 (67 ) 630 Net investment income $ 4,473 $ 4,193 $ 8,218 $ 8,614 __________________ (1) Changes in estimated fair value subsequent to purchase for investments still held as of the end of the respective periods included in net investment income were principally from Unit-linked investments, and were $165 million and ($174) million for the three months and six months ended June 30, 2018 , respectively, and $119 million and $449 million for the three months and six months ended June 30, 2017 , respectively. The Company invests in real estate joint ventures, other limited partnership interests and tax credit and renewable energy partnerships, and also does business through certain operating joint ventures, the majority of which are accounted for under the equity method. Net investment income from other limited partnership interests and operating joint ventures, accounted for under the equity method; and real estate joint ventures and tax credit and renewable energy partnerships, primarily accounted for under the equity method, totaled $97 million and $302 million for the three months and six months ended June 30, 2018 , respectively, and $121 million and $284 million for the three months and six months ended June 30, 2017 , respectively. Net Investment Gains (Losses) Components of Net Investment Gains (Losses) The components of net investment gains (losses) were as follows: Three Months Six Months 2018 2017 2018 2017 (In millions) Total gains (losses) on fixed maturity securities: Total OTTI losses recognized — by sector and industry: State and political subdivision $ — $ (3 ) $ — $ (3 ) OTTI losses on fixed maturity securities recognized in earnings — (3 ) — (3 ) Fixed maturity securities — net gains (losses) on sales and disposals (46 ) 45 (141 ) 43 Total gains (losses) on fixed maturi |