Goodwill (Changes in the Carrying Amount of Goodwill by Reporting Segment) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 22,745	$ 20,727
Acquisitions	1,454	2,209
Dispositions	(216)
Goodwill, Impairment Loss		(172)
Subsequent payments and adjustments, net	(8)	(19)
Goodwill, ending balance	23,975	22,745
UnitedHealthcare [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	17,837	17,851	[1]
Acquisitions	101	0
Dispositions	(2)
Goodwill, Impairment Loss		0
Subsequent payments and adjustments, net	(4)	(14)
Goodwill, ending balance	17,932	17,837
OptumHealth [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	760	573	[1]
Acquisitions	1,353	187
Dispositions	0
Goodwill, Impairment Loss		0
Subsequent payments and adjustments, net	0	0
Goodwill, ending balance	2,113	760
OptumInsight [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	3,308	1,463	[1]
Acquisitions	0	2,022
Dispositions	(214)
Goodwill, Impairment Loss		(172)
Subsequent payments and adjustments, net	(4)	(5)
Goodwill, ending balance	3,090	3,308
OptumRx [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	840	840	[1]
Acquisitions	0	0
Dispositions	0
Goodwill, Impairment Loss		0
Subsequent payments and adjustments, net	0	0
Goodwill, ending balance	$ 840	$ 840

[1] Prior period reportable segment financial information has been recast to conform to the 2011 presentation as discussed in Note 2 of Notes to the Consolidated Financial Statements.