Segment Financial Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement [Line Items]
Premiums, revenues - external customers	$ 28,840	$ 27,220	$ 56,955	$ 54,494
Services, revenues - external customers	2,447	2,244	4,851	4,356
Products, revenues - external customers	1,037	749	2,035	1,500
Investment and other income	250	195	441	398
Total revenues	32,574	30,408	64,282	60,748
Earnings from operations	2,552	2,401	4,606	4,540
Interest expense	(155)	(176)	(315)	(354)
Earnings before income taxes	2,397	2,225	4,291	4,186
Optum [Member]
Statement [Line Items]
Investment and other income	39	32	74	62
Total revenues	11,714	9,124	22,884	17,807
Earnings from operations	728	592	1,378	1,133
Interest expense	0	0	0	0
Earnings before income taxes	728	592	1,378	1,133
External Customers [Member]
Statement [Line Items]
Premiums, revenues - external customers	28,840	27,220	56,955	54,494
Services, revenues - external customers	2,447	2,244	4,851	4,356
Products, revenues - external customers	1,037	749	2,035	1,500
Total revenues	32,324	30,213	63,841	60,350
External Customers [Member] | Optum [Member]
Statement [Line Items]
Premiums, revenues - external customers	627	617	1,231	1,210
Services, revenues - external customers	801	707	1,619	1,425
Products, revenues - external customers	1,036	747	2,033	1,496
Total revenues	2,464	2,071	4,883	4,131
Intersegment [Member]
Statement [Line Items]
Total revenues	0	0	0	0
Intersegment [Member] | Optum [Member]
Statement [Line Items]
Total revenues	9,211	7,021	17,927	13,614
Operating Segments [Member] | UnitedHealthcare [Member]
Statement [Line Items]
Investment and other income	211	163	367	336
Total revenues	30,071	28,305	59,325	56,555
Earnings from operations	1,824	1,809	3,228	3,407
Interest expense	0	0	0	0
Earnings before income taxes	1,824	1,809	3,228	3,407
Operating Segments [Member] | Optumhealth [Member]
Statement [Line Items]
Investment and other income	39	32	74	62
Total revenues	2,586	2,411	5,166	4,853
Earnings from operations	224	216	435	436
Interest expense	0	0	0	0
Earnings before income taxes	224	216	435	436
Operating Segments [Member] | Optuminsight [Member]
Statement [Line Items]
Investment and other income	0	0	0	0
Total revenues	1,243	1,181	2,490	2,334
Earnings from operations	213	230	410	438
Interest expense	0	0	0	0
Earnings before income taxes	213	230	410	438
Operating Segments [Member] | Optumrx [Member]
Statement [Line Items]
Investment and other income	0	0	0	0
Total revenues	8,000	5,647	15,458	10,843
Earnings from operations	291	146	533	259
Interest expense	0	0	0	0
Earnings before income taxes	291	146	533	259
Operating Segments [Member] | External Customers [Member] | UnitedHealthcare [Member]
Statement [Line Items]
Premiums, revenues - external customers	28,213	26,603	55,724	53,284
Services, revenues - external customers	1,646	1,537	3,232	2,931
Products, revenues - external customers	1	2	2	4
Total revenues	29,860	28,142	58,958	56,219
Operating Segments [Member] | External Customers [Member] | Optumhealth [Member]
Statement [Line Items]
Premiums, revenues - external customers	627	617	1,231	1,210
Services, revenues - external customers	242	176	505	383
Products, revenues - external customers	4	5	11	10
Total revenues	873	798	1,747	1,603
Operating Segments [Member] | External Customers [Member] | Optuminsight [Member]
Statement [Line Items]
Premiums, revenues - external customers	0	0	0	0
Services, revenues - external customers	532	507	1,057	995
Products, revenues - external customers	14	14	40	33
Total revenues	546	521	1,097	1,028
Operating Segments [Member] | External Customers [Member] | Optumrx [Member]
Statement [Line Items]
Premiums, revenues - external customers	0	0	0	0
Services, revenues - external customers	27	24	57	47
Products, revenues - external customers	1,018	728	1,982	1,453
Total revenues	1,045	752	2,039	1,500
Operating Segments [Member] | Intersegment [Member] | UnitedHealthcare [Member]
Statement [Line Items]
Total revenues	0	0	0	0
Operating Segments [Member] | Intersegment [Member] | Optumhealth [Member]
Statement [Line Items]
Total revenues	1,674	1,581	3,345	3,188
Operating Segments [Member] | Intersegment [Member] | Optuminsight [Member]
Statement [Line Items]
Total revenues	697	660	1,393	1,306
Operating Segments [Member] | Intersegment [Member] | Optumrx [Member]
Statement [Line Items]
Total revenues	6,955	4,895	13,419	9,343
Optum Eliminations [Member]
Statement [Line Items]
Investment and other income	0	0	0	0
Total revenues	(115)	(115)	(230)	(223)
Earnings from operations	0	0	0	0
Interest expense	0	0	0	0
Earnings before income taxes	0	0	0	0
Optum Eliminations [Member] | External Customers [Member]
Statement [Line Items]
Premiums, revenues - external customers	0	0	0	0
Services, revenues - external customers	0	0	0	0
Products, revenues - external customers	0	0	0	0
Total revenues	0	0	0	0
Optum Eliminations [Member] | Intersegment [Member]
Statement [Line Items]
Total revenues	(115)	(115)	(230)	(223)
Corporate and Eliminations [Member]
Statement [Line Items]
Investment and other income	0	0	0	0
Total revenues	(9,211)	(7,021)	(17,927)	(13,614)
Earnings from operations	0	0	0	0
Interest expense	(155)	(176)	(315)	(354)
Earnings before income taxes	(155)	(176)	(315)	(354)
Corporate and Eliminations [Member] | External Customers [Member]
Statement [Line Items]
Premiums, revenues - external customers	0	0	0	0
Services, revenues - external customers	0	0	0	0
Products, revenues - external customers	0	0	0	0
Total revenues	0	0	0	0
Corporate and Eliminations [Member] | Intersegment [Member]
Statement [Line Items]
Total revenues	$ (9,211)	$ (7,021)	$ (17,927)	$ (13,614)