Segment Information (Schedule Of Segment Reporting Information, By Segment) (Details) (USD $) In Millions, unless otherwise specified	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
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											$ 35,106	$ 32,712	$ 29,927
Total services revenue											1,360	555	520
Total revenues - external customers											36,466	33,267	30,447
Total intersegment revenues											0	0	0
Investment income											366	329	296
Total revenues	9,056.0	9,301.0	9,284.0	9,191.0	8,276.0	[1]	8,351.0	8,589.0	[2]	8,380.0	36,832.0	33,596.0	30,743.0
Operating expenses, Benefits											28,823	27,117	24,784
Operating expenses, Operating costs											5,395	4,380	4,014
Operating expenses, Depreciation and amortization											270	245	237
Total operating expenses											34,488	31,742	29,035
Income (loss) from operations											2,344	1,854	1,708
Interest expense											109	105	106
Income (loss) before income taxes	313	699	726	497	174	[1]	622	536	[2]	417	2,235	1,749	1,602
Medicare Advantage [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											21,252	19,286	16,413
Medicare Stand-Alone PDP [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											2,578	2,319	2,328
Medicare [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											23,830	21,605	18,741
Fully-Insured [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											5,643	5,915	6,185
Specialty [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											1,059	967	889
Military Services [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											3,616	3,462	3,427
Medicaid And Other [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											958	763	685
Provider [Member]
Segment Reporting Information [Line Items]
Total services revenue											892	34	17
ASO And Other [Member]
Segment Reporting Information [Line Items]
Total services revenue											457	521	503
Pharmacy [Member]
Segment Reporting Information [Line Items]
Total services revenue											11	0	0
Services [Member]
Segment Reporting Information [Line Items]
Total intersegment revenues											0	0	0
Retail [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											21,402	19,052	18,349
Total services revenue											16	11	10
Total revenues - external customers											21,418	19,063	18,359
Total intersegment revenues											0	0	0
Investment income											76	80	88
Total revenues											21,494.0	19,143.0	18,447.0
Operating expenses, Benefits											17,383	15,624	14,988
Operating expenses, Operating costs											2,405	2,113	1,985
Operating expenses, Depreciation and amortization											119	117	115
Total operating expenses											19,907	17,854	17,088
Income (loss) from operations											1,587	1,289	1,359
Interest expense											0	0	0
Income (loss) before income taxes											1,587	1,289	1,359
Retail [Member] | Medicare Advantage [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											18,100	16,265	15,333
Retail [Member] | Medicare Stand-Alone PDP [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											2,317	1,959	2,323
Retail [Member] | Medicare [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											20,417	18,224	17,656
Retail [Member] | Fully-Insured [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											861	746	638
Retail [Member] | Specialty [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											124	82	55
Retail [Member] | Military Services [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Retail [Member] | Medicaid And Other [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Retail [Member] | Provider [Member]
Segment Reporting Information [Line Items]
Total services revenue											0	0	0
Retail [Member] | ASO And Other [Member]
Segment Reporting Information [Line Items]
Total services revenue											16	11	10
Retail [Member] | Pharmacy [Member]
Segment Reporting Information [Line Items]
Total services revenue											0	0	0
Retail [Member] | Services [Member]
Segment Reporting Information [Line Items]
Total intersegment revenues											0	0	0
Employer Group [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											8,877	9,080	7,466
Total services revenue											356	395	370
Total revenues - external customers											9,233	9,475	7,836
Total intersegment revenues											14	12	14
Investment income											48	42	48
Total revenues											9,295.0	9,529.0	7,898.0
Operating expenses, Benefits											7,318	7,486	6,289
Operating expenses, Operating costs											1,650	1,662	1,533
Operating expenses, Depreciation and amortization											85	93	89
Total operating expenses											9,053	9,241	7,911
Income (loss) from operations											242	288	(13)
Interest expense											0	0	0
Income (loss) before income taxes											242	288	(13)
Employer Group [Member] | Medicare Advantage [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											3,152	3,021	1,080
Employer Group [Member] | Medicare Stand-Alone PDP [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											8	5	5
Employer Group [Member] | Medicare [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											3,160	3,026	1,085
Employer Group [Member] | Fully-Insured [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											4,782	5,169	5,547
Employer Group [Member] | Specialty [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											935	885	834
Employer Group [Member] | Military Services [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Employer Group [Member] | Medicaid And Other [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Employer Group [Member] | Provider [Member]
Segment Reporting Information [Line Items]
Total services revenue											0	0	0
Employer Group [Member] | ASO And Other [Member]
Segment Reporting Information [Line Items]
Total services revenue											356	395	370
Employer Group [Member] | Pharmacy [Member]
Segment Reporting Information [Line Items]
Total services revenue											0	0	0
Employer Group [Member] | Services [Member]
Segment Reporting Information [Line Items]
Total intersegment revenues											14	12	14
Health And Well-Being Services [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Total services revenue											903	34	17
Total revenues - external customers											903	34	17
Total intersegment revenues											10,330	8,786	8,952
Investment income											0	0	0
Total revenues											11,233.0	8,820.0	8,969.0
Operating expenses, Benefits											0	0	0
Operating expenses, Operating costs											10,798	8,575	8,768
Operating expenses, Depreciation and amortization											82	26	18
Total operating expenses											10,880	8,601	8,786
Income (loss) from operations											353	219	183
Interest expense											0	0	0
Income (loss) before income taxes											353	219	183
Health And Well-Being Services [Member] | Medicare Advantage [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Health And Well-Being Services [Member] | Medicare Stand-Alone PDP [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Health And Well-Being Services [Member] | Medicare [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Health And Well-Being Services [Member] | Fully-Insured [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Health And Well-Being Services [Member] | Specialty [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Health And Well-Being Services [Member] | Military Services [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Health And Well-Being Services [Member] | Medicaid And Other [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Health And Well-Being Services [Member] | Provider [Member]
Segment Reporting Information [Line Items]
Total services revenue											892	34	17
Health And Well-Being Services [Member] | ASO And Other [Member]
Segment Reporting Information [Line Items]
Total services revenue											0	0	0
Health And Well-Being Services [Member] | Pharmacy [Member]
Segment Reporting Information [Line Items]
Total services revenue											11	0	0
Health And Well-Being Services [Member] | Services [Member]
Segment Reporting Information [Line Items]
Total intersegment revenues											8,510	7,494	8,003
Other Businesses [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											4,827	4,580	4,112
Total services revenue											85	115	123
Total revenues - external customers											4,912	4,695	4,235
Total intersegment revenues											0	0	0
Investment income											54	43	23
Total revenues											4,966.0	4,738.0	4,258.0
Operating expenses, Benefits											4,411	4,253	3,705
Operating expenses, Operating costs											461	475	431
Operating expenses, Depreciation and amortization											10	12	25
Total operating expenses											4,882	4,740	4,161
Income (loss) from operations											84	(2)	97
Interest expense											0	0	0
Income (loss) before income taxes											84	(2)	97
Other Businesses [Member] | Medicare Advantage [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Other Businesses [Member] | Medicare Stand-Alone PDP [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											253	355	0
Other Businesses [Member] | Medicare [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											253	355	0
Other Businesses [Member] | Fully-Insured [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Other Businesses [Member] | Specialty [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Other Businesses [Member] | Military Services [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											3,616	3,462	3,427
Other Businesses [Member] | Medicaid And Other [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											958	763	685
Other Businesses [Member] | Provider [Member]
Segment Reporting Information [Line Items]
Total services revenue											0	0	0
Other Businesses [Member] | ASO And Other [Member]
Segment Reporting Information [Line Items]
Total services revenue											85	115	123
Other Businesses [Member] | Pharmacy [Member]
Segment Reporting Information [Line Items]
Total services revenue											0	0	0
Other Businesses [Member] | Services [Member]
Segment Reporting Information [Line Items]
Total intersegment revenues											0	0	0
Eliminations/Corporate [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Total services revenue											0	0	0
Total revenues - external customers											0	0	0
Total intersegment revenues											(10,344)	(8,798)	(8,966)
Investment income											188	164	137
Total revenues											(10,156.0)	(8,634.0)	(8,829.0)
Operating expenses, Benefits											(289)	(246)	(198)
Operating expenses, Operating costs											(9,919)	(8,445)	(8,703)
Operating expenses, Depreciation and amortization											(26)	(3)	(10)
Total operating expenses											(10,234)	(8,694)	(8,911)
Income (loss) from operations											78	60	82
Interest expense											109	105	106
Income (loss) before income taxes											(31)	(45)	(24)
Eliminations/Corporate [Member] | Medicare Advantage [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Eliminations/Corporate [Member] | Medicare Stand-Alone PDP [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Eliminations/Corporate [Member] | Medicare [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Eliminations/Corporate [Member] | Fully-Insured [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Eliminations/Corporate [Member] | Specialty [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Eliminations/Corporate [Member] | Military Services [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Eliminations/Corporate [Member] | Medicaid And Other [Member]
Segment Reporting Information [Line Items]
Revenues - external customers, Premiums											0	0	0
Eliminations/Corporate [Member] | Provider [Member]
Segment Reporting Information [Line Items]
Total services revenue											0	0	0
Eliminations/Corporate [Member] | ASO And Other [Member]
Segment Reporting Information [Line Items]
Total services revenue											0	0	0
Eliminations/Corporate [Member] | Pharmacy [Member]
Segment Reporting Information [Line Items]
Total services revenue											0	0	0
Eliminations/Corporate [Member] | Services [Member]
Segment Reporting Information [Line Items]
Total intersegment revenues											(8,524)	(7,506)	(8,017)
Products [Member]
Segment Reporting Information [Line Items]
Total intersegment revenues											0	0	0
Products [Member] | Retail [Member]
Segment Reporting Information [Line Items]
Total intersegment revenues											0	0	0
Products [Member] | Employer Group [Member]
Segment Reporting Information [Line Items]
Total intersegment revenues											0	0	0
Products [Member] | Health And Well-Being Services [Member]
Segment Reporting Information [Line Items]
Total intersegment revenues											1,820	1,292	949
Products [Member] | Other Businesses [Member]
Segment Reporting Information [Line Items]
Total intersegment revenues											0	0	0
Products [Member] | Eliminations/Corporate [Member]
Segment Reporting Information [Line Items]
Total intersegment revenues											$ (1,820)	$ (1,292)	$ (949)

[1] Includes an expense of $139 million ($88 million after tax, or $0.52 per diluted common share) associated with reserve strengthening for our closed block of long-term care policies acquired in connection with the 2007 acquisition of KMG America Corporation as more fully described in Note 17 to the consolidated financial statements.

[2] Includes an expense of $147 million ($93 million after tax, or $0.55 per diluted common share) for the write-down of deferred acquisition costs associated with our individual commercial medical policies as more fully described in Note 17 to the consolidated financial statements.