Stock Incentive Plans - Stock-Based Compensation Expense (Details) - USD ($) $ in Millions |
8 Months Ended | 9 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Dec. 31, 2023 |
Dec. 31, 2023 |
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
|
| Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | |||||
| Stock-based compensation expense | $ 540 | $ 588 | $ 447 | ||
| Oak Street Health Inc. | |||||
| Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | |||||
| Stock-based compensation expense | $ 71 | 60 | |||
| Signify Health, Inc. | |||||
| Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | |||||
| Stock-based compensation expense | $ 72 | 41 | |||
| Restricted stock units and performance stock units | |||||
| Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | |||||
| Stock-based compensation expense | 461 | 497 | 369 | ||
| Stock options and SARs | |||||
| Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items] | |||||
| Stock-based compensation expense | $ 79 | $ 91 | $ 78 | ||