Segment Financial Information (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Premiums, revenues - external customers									$ 91,983,000,000	$ 85,405,000,000	$ 79,315,000,000
Services, revenues - external customers									6,613,000,000	5,819,000,000	5,306,000,000
Products, revenues - external customers									2,612,000,000	2,322,000,000	1,925,000,000
Total revenues - external customers									101,208,000,000	93,546,000,000	86,546,000,000
Total revenues - intersegment									0	0	0
Investment and other income									654,000,000	609,000,000	592,000,000
Total revenues	25,916,000,000	25,280,000,000	25,234,000,000	25,432,000,000	24,030,000,000	23,668,000,000	23,264,000,000	23,193,000,000	101,862,000,000	94,155,000,000	87,138,000,000
Earnings from operations	2,074,000,000	2,070,000,000	2,099,000,000	2,221,000,000	1,802,000,000	2,145,000,000	1,901,000,000	2,016,000,000	8,464,000,000	7,864,000,000	6,359,000,000
Interest expense									(505,000,000)	(481,000,000)	(551,000,000)
Earnings (loss) before income taxes									7,959,000,000	7,383,000,000	5,808,000,000
Total assets	67,889,000,000				63,063,000,000				67,889,000,000	63,063,000,000	59,045,000,000
Purchases of property, equipment and capitalized software									1,067,000,000	878,000,000	739,000,000
Depreciation and amortization									1,124,000,000	1,064,000,000	991,000,000
Goodwill, Impairment Loss										172,000,000
UnitedHealthcare [Member]
Premiums, revenues - external customers									90,487,000,000	84,158,000,000	78,251,000,000
Services, revenues - external customers									4,291,000,000	4,021,000,000	3,941,000,000
Products, revenues - external customers									0	0	0
Total revenues - external customers									94,778,000,000	88,179,000,000	82,192,000,000
Total revenues - intersegment									0	0	0
Investment and other income									558,000,000	551,000,000	538,000,000
Total revenues									95,336,000,000	88,730,000,000	82,730,000,000
Earnings from operations									7,203,000,000	6,740,000,000	4,833,000,000
Interest expense									0	0	0
Earnings (loss) before income taxes									7,203,000,000	6,740,000,000	4,833,000,000
Total assets	52,618,000,000				50,913,000,000				52,618,000,000	50,913,000,000	49,920,000,000
Purchases of property, equipment and capitalized software									635,000,000	525,000,000	482,000,000
Depreciation and amortization									680,000,000	725,000,000	679,000,000
Goodwill, Impairment Loss										0
Total Optum [Member]
Premiums, revenues - external customers									1,496,000,000	1,247,000,000	1,064,000,000
Services, revenues - external customers									2,322,000,000	1,798,000,000	1,365,000,000
Products, revenues - external customers									2,612,000,000	2,322,000,000	1,925,000,000
Total revenues - external customers									6,430,000,000	5,367,000,000	4,354,000,000
Total revenues - intersegment									22,127,000,000	18,206,000,000	16,028,000,000
Investment and other income									96,000,000	58,000,000	54,000,000
Total revenues									28,653,000,000	23,631,000,000	20,436,000,000
Earnings from operations									1,261,000,000	1,124,000,000	1,526,000,000
Interest expense									0	0	0
Earnings (loss) before income taxes									1,261,000,000	1,124,000,000	1,526,000,000
Total assets	15,567,000,000				12,419,000,000				15,567,000,000	12,419,000,000	9,057,000,000
Purchases of property, equipment and capitalized software									432,000,000	353,000,000	257,000,000
Depreciation and amortization									444,000,000	339,000,000	312,000,000
Goodwill, Impairment Loss										172,000,000
OptumHealth [Member]
Premiums, revenues - external customers									1,496,000,000	1,247,000,000	1,064,000,000
Services, revenues - external customers									628,000,000	331,000,000	274,000,000
Products, revenues - external customers									24,000,000	19,000,000	16,000,000
Total revenues - external customers									2,148,000,000	1,597,000,000	1,354,000,000
Total revenues - intersegment									4,461,000,000	2,912,000,000	2,805,000,000
Investment and other income									95,000,000	56,000,000	53,000,000
Total revenues									6,704,000,000	4,565,000,000	4,212,000,000
Earnings from operations									423,000,000	511,000,000	599,000,000
Interest expense									0	0	0
Earnings (loss) before income taxes									423,000,000	511,000,000	599,000,000
Total assets	6,756,000,000				3,897,000,000				6,756,000,000	3,897,000,000	3,190,000,000
Purchases of property, equipment and capitalized software									168,000,000	117,000,000	71,000,000
Depreciation and amortization									154,000,000	100,000,000	105,000,000
Goodwill, Impairment Loss										0
OptumInsight [Member]
Premiums, revenues - external customers									0	0	0
Services, revenues - external customers									1,616,000,000	1,403,000,000	1,042,000,000
Products, revenues - external customers									96,000,000	93,000,000	90,000,000
Total revenues - external customers									1,712,000,000	1,496,000,000	1,132,000,000
Total revenues - intersegment									958,000,000	845,000,000	691,000,000
Investment and other income									1,000,000	1,000,000	0
Total revenues									2,671,000,000	2,342,000,000	1,823,000,000
Earnings from operations									381,000,000	84,000,000	246,000,000
Interest expense									0	0	0
Earnings (loss) before income taxes									381,000,000	84,000,000	246,000,000
Total assets	5,308,000,000				5,435,000,000				5,308,000,000	5,435,000,000	2,775,000,000
Purchases of property, equipment and capitalized software									175,000,000	156,000,000	129,000,000
Depreciation and amortization									195,000,000	159,000,000	128,000,000
Goodwill, Impairment Loss										172,000,000
OptumRx [Member]
Premiums, revenues - external customers									0	0	0
Services, revenues - external customers									78,000,000	64,000,000	49,000,000
Products, revenues - external customers									2,492,000,000	2,210,000,000	1,819,000,000
Total revenues - external customers									2,570,000,000	2,274,000,000	1,868,000,000
Total revenues - intersegment									16,708,000,000	14,449,000,000	12,532,000,000
Investment and other income									0	1,000,000	1,000,000
Total revenues									19,278,000,000	16,724,000,000	14,401,000,000
Earnings from operations									457,000,000	529,000,000	681,000,000
Interest expense									0	0	0
Earnings (loss) before income taxes									457,000,000	529,000,000	681,000,000
Total assets	3,503,000,000				3,087,000,000				3,503,000,000	3,087,000,000	3,092,000,000
Purchases of property, equipment and capitalized software									89,000,000	80,000,000	57,000,000
Depreciation and amortization									95,000,000	80,000,000	79,000,000
Goodwill, Impairment Loss										0
Corporate and Intersegment Eliminations [Member]
Premiums, revenues - external customers									0	0	0
Services, revenues - external customers									0	0	0
Products, revenues - external customers									0	0	0
Total revenues - external customers									0	0	0
Total revenues - intersegment									(22,127,000,000)	(18,206,000,000)	(16,028,000,000)
Investment and other income									0	0	0
Total revenues									(22,127,000,000)	(18,206,000,000)	(16,028,000,000)
Earnings from operations									0	0	0
Interest expense									(505,000,000)	(481,000,000)	(551,000,000)
Earnings (loss) before income taxes									(505,000,000)	(481,000,000)	(551,000,000)
Total assets	(296,000,000)				(269,000,000)				(296,000,000)	(269,000,000)	68,000,000
Purchases of property, equipment and capitalized software									0	0	0
Depreciation and amortization									0	0	0
Goodwill, Impairment Loss										$ 0