Medical Claims Liability - Narrative (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||||
|---|---|---|---|---|---|---|
Sep. 30, 2024 |
Sep. 30, 2024 |
Sep. 30, 2023 |
Jun. 30, 2024 |
Mar. 31, 2024 |
Dec. 31, 2023 |
|
| Insurance [Abstract] | ||||||
| Amounts recorded as an adjustment to premium revenues related to minimum HBR and return of premium programs | $ 236 | $ 341 | ||||
| Short-duration insurance contracts, Incurred but not reported and expected development on reported claims | $ 12,654 | 12,654 | ||||
| Segment Reporting Information [Line Items] | ||||||
| Premium deficiency reserve liability increase (decrease) | (5) | |||||
| Medicare | ||||||
| Segment Reporting Information [Line Items] | ||||||
| Premium deficiency reserve liability | 245 | 245 | $ 335 | $ 300 | $ 250 | |
| Premium deficiency reserve liability increase (decrease) | $ (90) | $ (5) | ||||