Basis of Presentation (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Nature of Operations			UnitedHealth Group Incorporated (individually and together with its subsidiaries, “UnitedHealth Group” and the “Company”) is a health care and well-being company with a mission to help people live healthier lives and help make the health system work better for everyone. The Company’s two distinct, yet complementary businesses — Optum and UnitedHealthcare — are working to help build a modern, high-performing health system through improved access, affordability, outcomes and experiences for the individuals and organizations the Company is privileged to serve.
Accounts Receivable, after Allowance for Credit Loss, Current	$ 21,573		$ 21,573		$ 23,018
Revenue, Remaining Performance Obligation, Amount	$ 10,700		$ 10,700
Revenue, Remaining Performance Obligation, Percentage	50.00%		50.00%
Uncommitted Receivables Financing Facility			$ 3,300
Receivables sold under receivables financing facility	$ 3,200		3,200
Uncommitted Receivables Facility, Amount Collected but Not Remitted	130		130		1,000
Gain On Portfolio Actions			191
Amount remitted to financial institutions			2,000
Amount collected in 2026 related to receivables sold in 2025			1,000
Loss On Portfolio Actions	39
Uncommitted Receivables Facility Amount Collected			1,700
Operating costs	14,268	$ 13,778	29,658	$ 27,372
Investment and other income	1,223	$ 1,108	2,354	2,141
Medical costs			148,847	$ 151,996
United Health Foundation contribution
Restructuring and Other Actions			400
Loss contract reserves
Restructuring and Other Actions	50		187
Net valuation gains on equity securities
Restructuring and Other Actions	1		60
Restructuring and other actions
Operating costs			415
Investment and other income	1		75
Medical costs	50		187
Optum Insight
Gain On Portfolio Actions			524
Loss On Portfolio Actions	4
Restructuring and Other Actions			339
Optum Rx
Gain On Portfolio Actions			8
Optum Health
Loss On Portfolio Actions	35		341
Restructuring and Other Actions	$ 51		$ 186
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	3 years		3 years
unh:ProductsandservicesMember
Accounts Receivable, after Allowance for Credit Loss, Current	$ 9,500		$ 9,500		$ 9,700