| Document And Entity Information | 6 Months Ended |
| May 31, 2024 | |
| Document Information [Line Items] | |
| Entity Registrant Name | KAYNE ANDERSON ENERGY INFRASTRUCTURE FUND, INC. |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Entity Central Index Key | 0001293613 |
| Document Period End Date | May 31, 2024 |
| N-2 | 6 Months Ended |
| May 31, 2024 USD ($) shares | |
| Cover [Abstract] | |
| Entity Central Index Key | 0001293613 |
| Amendment Flag | false |
| Document Type | N-CSRS |
| Entity Registrant Name | KAYNE ANDERSON ENERGY INFRASTRUCTURE FUND, INC. |
| General Description of Registrant [Abstract] | |
| Investment Objectives and Practices [Text Block] | 1. Kayne Anderson Energy Infrastructure Fund, Inc. (the “Company” or “KYN”) was organized as a Maryland corporation on June 4, 2004, and is a non -diversified -end -tax |
| Risk Factors [Table Text Block] | 4. The Company’s investments are concentrated in the energy sector. A downturn in one or more industries within the energy sector, material declines in energy -related At May 31, 2024, the Company had the following investment concentrations: Category Percent of Energy Companies 100.0% Equity securities (1) 100.0% Energy Infrastructure Companies 95.2% Largest single issuer 9.9% Restricted securities 5.9% (1) For more information about the principal risks of investing in the Company, see Investment Objective, Policies and Risks in the Company’s most recently filed annual report. |
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | |
| Long Term Debt [Table Text Block] | The table below sets forth a summary of the issuances and key terms of each series of Notes outstanding during the six months ended May 31, 2024. Series Principal Principal Principal Unamortized Estimated Fixed/Floating Maturity GG $ 21,419 $ — $ 21,419 $ 19 $ 21,300 3.67% 4/16/25 KK 32,247 — 32,247 7 32,700 3.93% 7/30/24 OO 14,778 — 14,778 7 14,800 3.46% 10/29/24 PP 50,000 — 50,000 178 51,100 3-month SOFR + 151 bps 6/19/26 20,000 — 20,000 45 19,300 1.81% 6/19/25 RR 45,000 — 45,000 306 42,700 4.57% 5/18/32 SS 45,000 — 45,000 330 42,000 4.67% 8/2/34 TT 18,235 — 18,235 24 18,000 3.82% 8/8/25 UU 40,000 — 40,000 337 38,800 5.18% 3/29/33 VV — 25,000 25,000 290 25,400 5.79% 1/10/34 WW — 35,000 35,000 286 35,500 5.65% 5/22/31 XX — 40,000 40,000 333 40,600 5.79% 5/22/34 $ 286,679 $ 100,000 $ 386,679 $ 2,162 $ 382,200 |
| Long Term Debt, Principal | $ | $ 386,679 |
| Long Term Debt, Structuring [Text Block] | 11. At May 31, 2024, the Company had $386,679 aggregate principal amount of Notes outstanding. The table below sets forth a summary of the issuances and key terms of each series of Notes outstanding during the six months ended May 31, 2024. Series Principal Principal Principal Unamortized Estimated Fixed/Floating Maturity GG $ 21,419 $ — $ 21,419 $ 19 $ 21,300 3.67% 4/16/25 KK 32,247 — 32,247 7 32,700 3.93% 7/30/24 OO 14,778 — 14,778 7 14,800 3.46% 10/29/24 PP 50,000 — 50,000 178 51,100 3-month SOFR + 151 bps 6/19/26 20,000 — 20,000 45 19,300 1.81% 6/19/25 RR 45,000 — 45,000 306 42,700 4.57% 5/18/32 SS 45,000 — 45,000 330 42,000 4.67% 8/2/34 TT 18,235 — 18,235 24 18,000 3.82% 8/8/25 UU 40,000 — 40,000 337 38,800 5.18% 3/29/33 VV — 25,000 25,000 290 25,400 5.79% 1/10/34 WW — 35,000 35,000 286 35,500 5.65% 5/22/31 XX — 40,000 40,000 333 40,600 5.79% 5/22/34 $ 286,679 $ 100,000 $ 386,679 $ 2,162 $ 382,200 Holders of the fixed rate Series GG, KK, OO and QQ through SS Notes are entitled to receive cash interest payments semi -annually -annually As of May 31, 2024, each series of Notes was rated “AAA” by Kroll Bond Rating Agency (“KBRA”). In the event the credit rating on any series of Notes falls below “A-”, the interest rate on such series will increase by 1% during the period of time such series is rated below “A-”. The Company is required to maintain a current rating from one rating agency with respect to each series of Notes and is prohibited from having any rating of less than investment grade (“BBB-”) with respect to each series of Notes. The Notes were issued in private placement offerings to institutional investors and are not listed on any exchange or automated quotation system. The Notes contain various covenants related to other indebtedness, liens and limits on the Company’s overall leverage. Under the 1940 Act and the terms of the Notes, the Company may not declare dividends or make other distributions on shares of its common stock or make purchases of such shares if, at any time of the declaration, distribution or purchase, asset coverage with respect to senior securities representing indebtedness (including the Notes) would be less than 300%. The Notes are redeemable in certain circumstances at the option of the Company. The Notes are also subject to a mandatory redemption to the extent needed to satisfy certain requirements if the Company fails to meet an asset coverage ratio required by law and is not able to cure the coverage deficiency by the applicable deadline. The Notes are unsecured obligations of the Company and, upon liquidation, dissolution or winding up of the Company, will rank: (1) senior to all of the Company’s outstanding preferred shares; (2) senior to all of the Company’s outstanding common shares; (3) on parity with any unsecured creditors of the Company and any unsecured senior securities representing indebtedness of the Company; and (4) junior to any secured creditors of the Company. At May 31, 2024, the Company was in compliance with all covenants under the Notes agreements. |
| Long Term Debt, Dividends and Covenants [Text Block] | Holders of the fixed rate Series GG, KK, OO and QQ through SS Notes are entitled to receive cash interest payments semi -annually -annually As of May 31, 2024, each series of Notes was rated “AAA” by Kroll Bond Rating Agency (“KBRA”). In the event the credit rating on any series of Notes falls below “A-”, the interest rate on such series will increase by 1% during the period of time such series is rated below “A-”. The Company is required to maintain a current rating from one rating agency with respect to each series of Notes and is prohibited from having any rating of less than investment grade (“BBB-”) with respect to each series of Notes. The Notes were issued in private placement offerings to institutional investors and are not listed on any exchange or automated quotation system. The Notes contain various covenants related to other indebtedness, liens and limits on the Company’s overall leverage. Under the 1940 Act and the terms of the Notes, the Company may not declare dividends or make other distributions on shares of its common stock or make purchases of such shares if, at any time of the declaration, distribution or purchase, asset coverage with respect to senior securities representing indebtedness (including the Notes) would be less than 300%. The Notes are redeemable in certain circumstances at the option of the Company. The Notes are also subject to a mandatory redemption to the extent needed to satisfy certain requirements if the Company fails to meet an asset coverage ratio required by law and is not able to cure the coverage deficiency by the applicable deadline. The Notes are unsecured obligations of the Company and, upon liquidation, dissolution or winding up of the Company, will rank: (1) senior to all of the Company’s outstanding preferred shares; (2) senior to all of the Company’s outstanding common shares; (3) on parity with any unsecured creditors of the Company and any unsecured senior securities representing indebtedness of the Company; and (4) junior to any secured creditors of the Company. At May 31, 2024, the Company was in compliance with all covenants under the Notes agreements. |
| Outstanding Security, Title [Text Block] | Common stock |
| Outstanding Security, Authorized [Shares] | 193,876,226 |
| Outstanding Security, Held [Shares] | 169,126,038 |
| Preferred Stock [Member] | |
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | |
| Capital Stock [Table Text Block] | 12. At May 31, 2024, the Company had 6,123,774 The table below sets forth a summary of the key terms of each series of MRP Shares outstanding at May 31, 2024. Series Liquidation Unamortized Estimated Fixed/Floating Mandatory R $ 41,828 $ 236 $ 38,800 3.38% 2/11/27 S 49,775 528 43,700 3.60% 2/11/30 T 20,000 298 18,500 5.07% 8/2/32 U 9,491 19 9,400 4.07% 12/1/24 V 20,000 150 20,100 3-month SOFR + 201 bps 6/1/26 W 12,000 110 11,000 2.44% 9/1/26 $ 153,094 $ 1,341 $ 141,500 Holders of the MRP Shares are entitled to receive cumulative cash dividend payments on the first business day following each quarterly period (the last day of February, May 31, August 31 and November 30). As of May 31, 2024, each series of MRP Shares was rated “A+” by KBRA. The dividend rate on the Company’s MRP Shares will increase if the credit rating is downgraded below “A” (as determined by the lowest credit rating assigned). Further, the annual dividend rate for all series of MRP Shares will increase by 4.0% if no ratings are maintained, and the annual dividend rate will increase by 5.0% if the Company fails to make a dividend or certain other payments. The MRP Shares rank senior to all of the Company’s outstanding common shares and on parity with any other preferred stock. The MRP Shares are redeemable in certain circumstances at the option of the Company and are also subject to a mandatory redemption if the Company fails to meet a total leverage (debt and preferred stock) asset coverage ratio of 225%. Under the terms of the MRP Shares, the Company may not declare dividends or pay other distributions on shares of its common stock or make purchases of such shares if, at any time of the declaration, distribution or purchase, asset coverage with respect to total leverage would be less than 225%. The holders of the MRP Shares have one vote per share and will vote together with the holders of common stock as a single class except on matters affecting only the holders of MRP Shares or the holders of common stock. The holders of the MRP Shares, voting separately as a single class, have the right to elect at least two directors of the Company. At May 31, 2024, the Company was in compliance with the asset coverage requirement of its MRP Shares. |
| Security Dividends [Text Block] | Under the terms of the MRP Shares, the Company may not declare dividends or pay other distributions on shares of its common stock or make purchases of such shares if, at any time of the declaration, distribution or purchase, asset coverage with respect to total leverage would be less than 225%. |
| Security Voting Rights [Text Block] | The holders of the MRP Shares have one vote per share and will vote together with the holders of common stock as a single class except on matters affecting only the holders of MRP Shares or the holders of common stock. The holders of the MRP Shares, voting separately as a single class, have the right to elect at least two directors of the Company. |
| Security Preemptive and Other Rights [Text Block] | The MRP Shares rank senior to all of the Company’s outstanding common shares and on parity with any other preferred stock. The MRP Shares are redeemable in certain circumstances at the option of the Company and are also subject to a mandatory redemption if the Company fails to meet a total leverage (debt and preferred stock) asset coverage ratio of 225%. |
| Common Stock [Member] | |
| Capital Stock, Long-Term Debt, and Other Securities [Abstract] | |
| Capital Stock [Table Text Block] | 13. As of May 31, 2024, the Company had 193,876,226 During the six months ended May 31, 2024, there were no common stock transactions. Transactions in common shares for the fiscal year ended November 30, 2023, were as follows: Shares outstanding at November 30, 2022 136,131,530 Shares issued in connection with merger of KMF 32,994,508 Shares outstanding at November 30, 2023 169,126,038 |
| Security Title [Text Block] | common stock |
