Health Care Costs Payable - Liability for Unpaid Claims and Claims Adjustment Expense (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Reinsurance recoverables	$ 90	$ 81	$ 5
Other non-insurance health care costs payable	2,549
Total health care costs payable	15,399	$ 15,064	$ 12,049
Health Insurance Product Line
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Total outstanding liabilities for health care costs payable, net of reinsurance	12,526
Reinsurance recoverables	90			$ 5
Insurance lines other than short duration	$ 234