| 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] | Year Summary for First PEO 1 Summary for Second PEO 2 Compensation Actually Paid to First PEO 1,3 Compensation Actually Paid to Second PEO 2,3 Average 4 Average 4,5 Value of Initial Fixed $100 Adjusted 7 Total Peer Group 6 Net 2022 $ 13,246,447 $ 7,599,513 $ 12,622,902 $ 6,829,908 $ 6,659,921 $ 6,508,126 $ 130.44 $ 169.46 $ 1,202 $ 5.78 2021 — 20,637,990 — 42,314,846 9,904,692 8,682,563 131.06 159.43 1,347 5.15 2020 — 24,956,777 — 24,990,265 8,575,674 8,110,409 95.48 114.87 1,808 5.00 | | |
| Company Selected Measure Name | Adjusted Diluted EPS | | |
| Named Executive Officers, Footnote [Text Block] | Represents compensation for Ms. London, the Company's current CEORepresents compensation for Mr. Neidorff, the Company's former CEO.Non-PEO NEOs for the applicable years were as follows: 2022 - Andrew Asher, Kenneth Fasola, Christopher Koster, Brent Layton, James Murray, and David Thomas; 2021 - Andrew Asher, Jesse Hunter, Christopher Koster, Brent Layton, Sarah London, and Jeffrey Schwaneke; and 2020 - Mark Brooks, Kenneth Burdick, Brandy Burkhalter, Jesse Hunter, and Jeffrey Schwaneke. | | |
| Adjustment To PEO Compensation, Footnote [Text Block] | PEO Compensation Actually Paid. The amounts in the following table represent each of the amounts deducted and added to the equity award values for the PEOs for the applicable year for purposes of computing the "compensation actually paid" amounts appearing in this column of the Pay Versus Performance table: 2022 2022 2021 2020 PEO Summary Compensation Table Total $ 13,246,447 $ 7,599,513 $ 20,637,990 $ 24,956,777 SCT "Stock Awards Total" column value (7,624,974) — (12,750,020) (14,932,500) SCT "Option Awards" column value — — (2,249,984) (2,941,500) Year-end fair value of outstanding equity awards granted in applicable year 7,336,041 — 15,111,905 17,971,500 Change in fair value of outstanding equity awards granted in prior years (411,063) (231,094) 14,470,156 (3,157,935) Change in fair value of prior-year equity awards vested in applicable year 76,451 1,503,016 7,094,799 3,093,923 Change in fair value of prior-year equity awards — (2,041,527) — — PEO Compensation Actually Paid $ 12,622,902 $ 6,829,908 $ 42,314,846 $ 24,990,265 | | |
| Non-PEO NEO Average Total Compensation Amount | $ 6,659,921 | $ 9,904,692 | $ 8,575,674 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 6,508,126 | 8,682,563 | 8,110,409 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | Average Non-PEO NEO Compensation Actually Paid. The amounts in the following table represent each of the amounts deducted and added to the equity award values for the non-PEO NEOs for the applicable year for purposes of computing the "compensation actually paid" amounts appearing in this column of the Pay Versus Performance table: 2022 2021 2020 Average Non-PEO NEO Summary Compensation Table Total $ 6,659,921 $ 9,904,692 $ 8,575,674 SCT "Stock Awards Total" column value (3,591,638) (6,702,115) (6,049,007) SCT "Option Awards" column value — (312,500) — Year-end fair value of outstanding equity awards 3,579,477 6,597,686 5,934,979 Change in fair value of outstanding equity awards (144,408) 1,968,206 (661,445) Change in fair value of prior-year equity awards 4,774 505,643 310,208 Change in fair value of prior-year equity awards — (3,279,049) — Average Non-PEO NEO Compensation Actually Paid $ 6,508,126 $ 8,682,563 $ 8,110,409 | | |
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | Compensation Actually Paid _____ _______________ _______ CAP to Second PEO ($ in millions) CAP to First PEO ($ in millions) Average Compensation Actually Paid to Company TSR S&P Supercomposite Managed Healthcare Index TSR | | |
| Compensation Actually Paid vs. Net Income [Text Block] | Compensation Actually Paid ___________ vs. Net Income _____ CAP to Second PEO ($ in millions) CAP to First PEO ($ in millions) Average Compensation Actually Paid to Non-PEO NEOs ($ in millions) Net Income ($ in billions) | | |
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | Compensation Actually Paid 1 CAP to Second PEO ($ in millions) CAP to First PEO ($ in millions) Average Compensation Actually Paid to Non-PEO NEOs ($ in millions) Adjusted Diluted EPS 1 Represents non-GAAP measure. Refer to Appendix A for reconciliation of non-GAAP measures. | | |
| Total Shareholder Return Vs Peer Group [Text Block] | Compensation Actually Paid _____ _______________ _______ CAP to Second PEO ($ in millions) CAP to First PEO ($ in millions) Average Compensation Actually Paid to Company TSR S&P Supercomposite Managed Healthcare Index TSR | | |
| Tabular List [Table Text Block] | Most Important Performance Measures Adjusted Diluted EPS Adjusted Pre-tax Margin Adjusted Net Earnings Margin Revenue Growth Compound Annual Growth Rates Total Shareholder Return (TSR) | | |
| Total Shareholder Return Amount | $ 130.44 | 131.06 | 95.48 |
| Peer Group Total Shareholder Return Amount | 169.46 | 159.43 | 114.87 |
| Net Income (Loss) | $ 1,202,000,000 | $ 1,347,000,000 | $ 1,808,000,000 |
| Additional 402(v) Disclosure [Text Block] | Represents the Total Shareholder Return for the S&P Supercomposite Managed Healthcare Index. | | |
| Measure [Axis]: 1 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Total Shareholder Return | | |
| Measure [Axis]: 2 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Other Performance Measure Amount | 5.78 | 5.15 | 5 |
| Non-GAAP Measure Description [Text Block] | The Company has identified Adjusted Diluted EPS, a non-GAAP measure, as our company-selected measure, as it represents the most important financial performance measure used to link compensation actually paid to the PEOs and the non-PEO NEOs in 2022 to the Company's performance. See Appendix A for reconciliation of non-GAAP measures. | | |
| London [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| PEO Total Compensation Amount | $ 13,246,447 | | |
| PEO Actually Paid Compensation Amount | $ 12,622,902 | | |
| PEO Name | London | | |
| Neidorff [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| PEO Total Compensation Amount | $ 7,599,513 | $ 20,637,990 | $ 24,956,777 |
| PEO Actually Paid Compensation Amount | $ 6,829,908 | $ 42,314,846 | $ 24,990,265 |
| PEO Name | Neidorff | Neidorff | Neidorff |
| PEO [Member] | Measure [Axis]: 1 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Total Shareholder Return (TSR) | | |
| PEO [Member] | Measure [Axis]: 2 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Adjusted Diluted EPS | | |
| PEO [Member] | Measure [Axis]: 3 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Adjusted Pre-tax Margin | | |
| PEO [Member] | Measure [Axis]: 4 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Adjusted Net Earnings Margin | | |
| PEO [Member] | Measure [Axis]: 5 | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Measure Name | Revenue Growth Compound Annual Growth Rates | | |
| PEO [Member] | London [Member] | Stock Awards Total Value [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | $ (7,624,974) | | |
| PEO [Member] | London [Member] | Option Awards Value [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 0 | | |
| PEO [Member] | London [Member] | Equity Awards Reported Value [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 7,336,041 | | |
| PEO [Member] | London [Member] | Equity Awards Granted in Prior Years [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (411,063) | | |
| PEO [Member] | London [Member] | Equity Awards Granted in Prior Years, Vested [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 76,451 | | |
| PEO [Member] | London [Member] | Equity Awards Granted in Prior Years, Cancelled [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 0 | | |
| PEO [Member] | Neidorff [Member] | Stock Awards Total Value [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 0 | $ (12,750,020) | $ (14,932,500) |
| PEO [Member] | Neidorff [Member] | Option Awards Value [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 0 | (2,249,984) | (2,941,500) |
| PEO [Member] | Neidorff [Member] | Equity Awards Reported Value [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 0 | 15,111,905 | 17,971,500 |
| PEO [Member] | Neidorff [Member] | Equity Awards Granted in Prior Years [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (231,094) | 14,470,156 | (3,157,935) |
| PEO [Member] | Neidorff [Member] | Equity Awards Granted in Prior Years, Vested [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 1,503,016 | 7,094,799 | 3,093,923 |
| PEO [Member] | Neidorff [Member] | Equity Awards Granted in Prior Years, Cancelled [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (2,041,527) | 0 | 0 |
| Non-PEO NEO [Member] | Stock Awards Total Value [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (3,591,638) | (6,702,115) | (6,049,007) |
| Non-PEO NEO [Member] | Option Awards Value [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 0 | (312,500) | 0 |
| Non-PEO NEO [Member] | Equity Awards Reported Value [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 3,579,477 | 6,597,686 | 5,934,979 |
| Non-PEO NEO [Member] | Equity Awards Granted in Prior Years [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | (144,408) | 1,968,206 | (661,445) |
| Non-PEO NEO [Member] | Equity Awards Granted in Prior Years, Vested [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | 4,774 | 505,643 | 310,208 |
| Non-PEO NEO [Member] | Equity Awards Granted in Prior Years, Cancelled [Member] | | | |
| Pay vs Performance Disclosure [Table] | | | |
| Adjustment to Compensation Amount | $ 0 | $ (3,279,049) | $ 0 |
