| Pay vs Performance Disclosure | 12 Months Ended |
| Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) |
| Pay vs Performance Disclosure [Table] | | | |
| Pay vs Performance [Table Text Block] | As required by Section 953(a) of the Dodd-Frank Wall Street Reform and Consumer Protection Act and Item 402(v) of Regulation S-K, we have prepared this pay versus performance disclosure, which serves to further demonstrate the alignment of our executive compensation program with stockholder interests. Value of Initial Fixed $100 Investment Based on: Year Summary Compensation Table Total for Current CEO ($) 1 Summary Compensation Table Total for Prior CEO ($) 1 Compensation Actually Paid to Current CEO ($) 1 Compensation Actually Paid to Prior CEO ($) 1 Average Summary Compensation Table Total for Non-CEO NEOs 2 Average Compensation Actually Paid to Non-CEO NEOs 2 Total Stock-holder Return 3 Peer Group Total Stock-holder Return 3,4 Net Income ($ in Millions) 5 Relative Annual Economic Return 6 2022 $7,646,700 N/A $3,653,990 N/A $4,266,463 $1,425,320 $81.01 $69.20 $(1,190) (2.1)% 2021 $6,949,900 $11,254,900 $7,745,878 $15,106,695 $2,952,885 $3,317,861 $103.51 $91.50 $749 9.9% 2020 N/A $15,826,500 N/A $13,076,972 $3,623,342 $3,153,609 $98.36 $77.80 $(266) 28.8% 1. During 2022, our CEO was Peter Federico (“Current CEO”). During 2021, our CEOs were Peter Federico and Gary Kain (“Prior CEO”). Messrs. Kain and Federico each served as CEO of the Company for a six month period during 2021. Compensation totals during 2021 reflect the full-year compensation received by each of Messrs. Kain and Federico and do not reflect pro-rated payment for the period that each individual served as CEO. During 2020, our CEO was Gary Kain. 2. During 2022, our remaining NEOs consisted of Messrs. Kain, Kuehl and Pollack and Ms. Bell. During 2021, our remaining NEOs consisted of Messrs. Kuehl, Pas, and Pollack and Ms. Bell. During 2020, our remaining NEOs consisted of Messrs. Federico, Kuehl, and Pollack and Ms. Bell. For more details regarding how the amounts in this column are calculated, refer to the “Adjustments to Summary Compensation Tables to Determine Compensation Actually Paid" tables immediately below. 3. Total Stockholder Return and Peer Group Total Stockholder Return assumes $100 invested at December 31, 2019. 4. As permitted by SEC rules, the Peer Group referenced for purpose of the Total Stockholder Return comparison consists of the Bloomberg Mortgage REIT Index. 5. Reflects after-tax net income attributable to stockholders prepared in accordance with GAAP for each of the years shown. 6. The Company has designated “ Relative Annual Economic Return” as its Company Selected Measure, as this is the largest financial component of our 2022 Corporate Scorecard and our most important financial measure (that is not otherwise required to be disclosed in this table) used by us to link compensation actually paid to our NEOs to Company performance. Relative Annual Economic Return compares the economic return of AGNC to that of the average of the Agency REIT Peer Group. For purposes of AGNC's Corporate Scorecard, relative annual economic return is calculated on an October 1 - September 30 year, but consistent with the requirements of Regulation S-K, it is calculated for purposes of this table on a calendar year basis. Additional details regarding the calculation of Relative Annual Economic Return and the companies included in the Agency REIT Peer Group for 2022 are included in the discussion of our 2022 Corporate Scorecard on page 33. For 2020, the peer group consisted of NLY, ANH, ARR, CMO, DX, IVR, and TWO. For 2021, the component companies were NLY, ARR, CMO, DX, IVR, and TWO, although CMO was included only through September 30, 2021 as a result of its acquisition. ANH was not included in 2021 as a result of its acquisition. | | |
| Non-PEO NEO Average Total Compensation Amount | $ 4,266,463 | $ 2,952,885 | $ 3,623,342 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 1,425,320 | 3,317,861 | 3,153,609 |
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | The following graph illustrates the relationship between compensation actually paid to our NEOs and AGNC’s total stockholder return on a cumulative basis assuming investment of $100 on December 31, 2019: | | |
| Compensation Actually Paid vs. Net Income [Text Block] | The following graph illustrates the relationship between compensation actually paid to our NEOs and AGNC’s net income on an annual basis: | | |
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | The following graph illustrates the relationship between compensation actually paid to our NEOs and AGNC’s economic return relative to the AGNC Peer Group on an annual basis: | | |
| Total Shareholder Return Vs Peer Group [Text Block] | The relationship between AGNC’s total stockholder return and the total stockholder return of The Bloomberg Mortgage REIT Index on a cumulative basis is shown below: | | |
| Tabular List [Table Text Block] | Since its adoption in 2016, our current compensation program has linked the compensation of our NEOs to achievement of short- and long-term financial and strategic goals. Our 2022 Corporate Scorecard consists 75% of financial metrics and 25% of strategic and operational measures. A significant percentage of our NEOs’ compensation is in the form of equity awards that vest over three years, and in 2022, 67% of these awards to NEOs were performance vesting. In 2022, incentive compensation served as a material element of each NEO’s compensation package and serves to further align compensation to Company performance. The most important financial performance measures utilized by the Compensation Committee to link compensation paid to our NEOs to AGNC's performance for 2022 were: • Annual Economic Return Relative to the Agency REIT Peer Group • Absolute Annual Economic Return • Ratio of Price-to-Tangible Book Value Relative to the Agency REIT Peer Group | | |
| Total Shareholder Return Amount | $ 81.01 | 103.51 | 98.36 |
| Peer Group Total Shareholder Return Amount | 69.20 | 91.50 | 77.80 |
| Net Income (Loss) | $ (1,190,000,000) | $ 749,000,000 | $ (266,000,000) |
| Company Selected Measure Amount | (0.021) | 0.099 | 0.288 |
| PEO Total Compensation Amount - Current | $ 7,646,700 | $ 6,949,900 | |
| PEO Actually Paid Compensation Amount - Current | $ 3,653,990 | 7,745,878 | |
| PEO Total Compensation Amount - Prior | | 11,254,900 | $ 15,826,500 |
| PEO Actually Paid Compensation Amount - Prior | | $ 15,106,695 | $ 13,076,972 |
| Adjustment to PEO and Non-PEO NEO Compensation Footnote | Compensation Actually Paid represents the Summary Compensation Table Totals adjusted for the following items: Year 2022 Adjustments to Summary Compensation Table Totals to Determine Compensation Actually Paid Current CEO Prior CEO Average for Non-CEO-NEOs Deduction for amounts reported under the Stock Awards Column in the Summary Compensation Table $ (4,500,000) N/A $ (2,262,500) Increase for fair value at year-end of awards granted during year that remain unvested as of year-end $ 2,663,407 N/A $ 1,339,108 Increase/(Deduction) for change in fair value from prior year-end to current year-end of awards granted prior to year that were outstanding and unvested as of year-end $ (2,009,058) N/A $ (1,669,332) Increase/(Deduction) for change in fair value from prior year-end to vesting date of awards granted prior to year that vested during year $ (147,059) N/A $ (248,419) Total adjustments $ (3,992,710) N/A $ (2,841,143) Year 2021 Adjustments to Summary Compensation Table Totals to Determine Compensation Actually Paid Current CEO Prior CEO Average for Non-CEO-NEOs Deduction for amounts reported under the Stock Awards Column in the Summary Compensation Table $ (3,400,000) $ (6,150,000) $ (1,257,500) Increase for fair value at year-end of awards granted during year that remain unvested as of year-end $ 3,443,197 $ 6,228,139 $ 1,273,459 Increase/(Deduction) for change in fair value from prior year-end to current year-end of awards granted prior to year that were outstanding and unvested as of year-end $ 635,848 $ 3,420,757 $ 316,660 Increase/(Deduction) for change in fair value from prior year-end to vesting date of awards granted prior to year that vested during year $ 116,933 $ 352,899 $ 32,357 Total adjustments $ 795,978 $ 3,851,795 $ 364,976 Year 2020 Adjustments to Summary Compensation Table Totals to Determine Compensation Actually Paid Current CEO Prior CEO Average for Non-CEO-NEOs Deduction for amounts reported under the Stock Awards Column in the Summary Compensation Table N/A $ (8,100,000) $ (1,406,250) Increase for fair value at year-end of awards granted during year that remain unvested as of year-end N/A $ 7,117,718 $ 1,235,711 Increase/(Deduction) for change in fair value from prior year-end to current year-end of awards granted prior to year that were outstanding and unvested as of year-end N/A $ (14,176) $ (19,510) Increase/(Deduction) for change in fair value from prior year-end to vesting date of awards granted prior to year that vested during year N/A $ (1,753,070) $ (279,684) Total adjustments N/A $ (2,749,528) $ (469,733) | | |
| Measure [Axis]: 1 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Annual Economic Return Relative to the Agency REIT Peer Group | | |
| Measure [Axis]: 2 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Absolute Annual Economic Return | | |
| Measure [Axis]: 3 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Ratio of Price-to-Tangible Book Value Relative to the Agency REIT Peer Group | | |
