Segment Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement [Line Items]
Premiums, revenues - unaffiliated customers	$ 226,233	$ 201,478	$ 189,699
Investment and other income	2,324	1,502	1,886
Total revenues	287,597	257,141	242,155
Earnings from operations	23,970	22,405	19,685
Interest expense	(1,660)	(1,663)	(1,704)
Earnings before income taxes	22,310	20,742	17,981
Total assets	212,206	197,289	173,889
Purchases of property, equipment and capitalized software	2,454	2,051	2,071
Depreciation and amortization	3,103	2,891	2,720
Products
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	34,437	34,145	31,597
Services
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	24,603	20,016	18,973
Optum
Statement [Line Items]
Investment and other income	1,467	770	749
Total revenues	155,565	136,308	112,950
Earnings from operations	11,995	10,046	9,359
Interest expense	0	0	0
Earnings before income taxes	11,995	10,046	9,359
Total assets	117,523	106,778	91,971
Purchases of property, equipment and capitalized software	1,659	1,364	1,230
Depreciation and amortization	2,099	1,971	1,794
Unaffiliated Customers
Statement [Line Items]
Premiums, revenues - unaffiliated customers	226,233	201,478	189,699
Total revenues	285,273	255,639	240,269
Unaffiliated Customers | Products
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	34,437	34,145	31,597
Unaffiliated Customers | Services
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	24,603	20,016	18,973
Unaffiliated Customers | Optum
Statement [Line Items]
Premiums, revenues - unaffiliated customers	13,852	9,799	5,916
Total revenues	63,231	55,496	47,564
Unaffiliated Customers | Optum | Products
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	34,437	34,145	31,597
Unaffiliated Customers | Optum | Services
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	14,942	11,552	10,051
Affiliated Customers
Statement [Line Items]
Total revenues	0	0	0
Affiliated Customers | Optum
Statement [Line Items]
Total revenues	90,867	80,042	64,637
Operating Segments | UnitedHealthcare
Statement [Line Items]
Investment and other income	857	732	1,137
Total revenues	222,899	200,875	193,842
Earnings from operations	11,975	12,359	10,326
Interest expense	0	0	0
Earnings before income taxes	11,975	12,359	10,326
Total assets	102,967	98,229	88,250
Purchases of property, equipment and capitalized software	795	687	841
Depreciation and amortization	1,004	920	926
Operating Segments | Optum Health
Statement [Line Items]
Investment and other income	1,053	680	672
Total revenues	54,065	39,808	30,317
Earnings from operations	4,462	3,434	2,963
Interest expense	0	0	0
Earnings before income taxes	4,462	3,434	2,963
Total assets	60,474	52,073	40,444
Purchases of property, equipment and capitalized software	791	715	573
Depreciation and amortization	818	703	565
Operating Segments | Optum Insight
Statement [Line Items]
Investment and other income	237	39	21
Total revenues	12,199	10,802	10,006
Earnings from operations	3,398	2,725	2,494
Interest expense	0	0	0
Earnings before income taxes	3,398	2,725	2,494
Total assets	16,868	15,425	15,181
Purchases of property, equipment and capitalized software	567	461	495
Depreciation and amortization	684	670	672
Operating Segments | Optum Rx
Statement [Line Items]
Investment and other income	177	51	56
Total revenues	91,314	87,498	74,288
Earnings from operations	4,135	3,887	3,902
Interest expense	0	0	0
Earnings before income taxes	4,135	3,887	3,902
Total assets	40,181	39,280	36,346
Purchases of property, equipment and capitalized software	301	188	162
Depreciation and amortization	597	598	557
Operating Segments | Unaffiliated Customers | UnitedHealthcare
Statement [Line Items]
Premiums, revenues - unaffiliated customers	212,381	191,679	183,783
Total revenues	222,042	200,143	192,705
Operating Segments | Unaffiliated Customers | UnitedHealthcare | Products
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	0	0	0
Operating Segments | Unaffiliated Customers | UnitedHealthcare | Services
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	9,661	8,464	8,922
Operating Segments | Unaffiliated Customers | Optum Health
Statement [Line Items]
Premiums, revenues - unaffiliated customers	13,852	9,799	5,916
Total revenues	23,778	16,647	11,679
Operating Segments | Unaffiliated Customers | Optum Health | Products
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	32	33	31
Operating Segments | Unaffiliated Customers | Optum Health | Services
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	9,894	6,815	5,732
Operating Segments | Unaffiliated Customers | Optum Insight
Statement [Line Items]
Premiums, revenues - unaffiliated customers	0	0	0
Total revenues	4,095	3,822	3,746
Operating Segments | Unaffiliated Customers | Optum Insight | Products
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	159	135	116
Operating Segments | Unaffiliated Customers | Optum Insight | Services
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	3,936	3,687	3,630
Operating Segments | Unaffiliated Customers | Optum Rx
Statement [Line Items]
Premiums, revenues - unaffiliated customers	0	0	0
Total revenues	35,358	35,027	32,139
Operating Segments | Unaffiliated Customers | Optum Rx | Products
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	34,246	33,977	31,450
Operating Segments | Unaffiliated Customers | Optum Rx | Services
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	1,112	1,050	689
Operating Segments | Affiliated Customers | UnitedHealthcare
Statement [Line Items]
Total revenues	0	0	0
Operating Segments | Affiliated Customers | Optum Health
Statement [Line Items]
Total revenues	29,234	22,481	17,966
Operating Segments | Affiliated Customers | Optum Insight
Statement [Line Items]
Total revenues	7,867	6,941	6,239
Operating Segments | Affiliated Customers | Optum Rx
Statement [Line Items]
Total revenues	55,779	52,420	42,093
Optum Eliminations
Statement [Line Items]
Investment and other income	0	0	0
Total revenues	(2,013)	(1,800)	(1,661)
Earnings from operations	0	0	0
Interest expense	0	0	0
Earnings before income taxes	0	0	0
Total assets	0	0	0
Purchases of property, equipment and capitalized software	0	0	0
Depreciation and amortization	0	0	0
Optum Eliminations | Unaffiliated Customers
Statement [Line Items]
Premiums, revenues - unaffiliated customers	0	0	0
Total revenues	0	0	0
Optum Eliminations | Unaffiliated Customers | Products
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	0	0	0
Optum Eliminations | Unaffiliated Customers | Services
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	0	0	0
Optum Eliminations | Affiliated Customers
Statement [Line Items]
Total revenues	(2,013)	(1,800)	(1,661)
Corporate and Eliminations
Statement [Line Items]
Investment and other income	0	0	0
Total revenues	(90,867)	(80,042)	(64,637)
Earnings from operations	0	0	0
Interest expense	(1,660)	(1,663)	(1,704)
Earnings before income taxes	(1,660)	(1,663)	(1,704)
Total assets	(8,284)	(7,718)	(6,332)
Purchases of property, equipment and capitalized software	0	0	0
Depreciation and amortization	0	0	0
Corporate and Eliminations | Unaffiliated Customers
Statement [Line Items]
Premiums, revenues - unaffiliated customers	0	0	0
Total revenues	0	0	0
Corporate and Eliminations | Unaffiliated Customers | Products
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	0	0	0
Corporate and Eliminations | Unaffiliated Customers | Services
Statement [Line Items]
Revenue from Products and Services - unaffiliated customers	0	0	0
Corporate and Eliminations | Affiliated Customers
Statement [Line Items]
Total revenues	$ (90,867)	$ (80,042)	$ (64,637)