SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Payments of Federal Government’s Claims and Related Reimbursements Under Deposit Accounting (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Health care cost payments	$ (5,641)	$ (7,477)	$ (7,073)
Health care cost reimbursements	5,567	7,385	7,130
Net (payments) reimbursements	$ (74)	$ (92)	$ 57

The difference between health care cost payments and reimbursements related to the TRICARE South Region contract.

No definition available.

Name:	hum_HealthCareCostPaymentsAndReimbursementsNet
Namespace Prefix:	hum_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration