Schedule I-Parent Company Financial Information (Condensed Statements Of Operations) (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
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 costs											5,395	4,380	4,014
Depreciation											249	225	213
Interest											109	105	106
(Benefit) provision for income taxes											816	650	562
Net income	199	445	460	315	107	[1]	393	340	[2]	259	1,419	1,099	1,040
Net unrealized investment gains, net of tax expense of $109 million in 2011, $47 million in 2010, and $131 million in 2009											190	82	230
Less: Reclassification adjustment for net realized gains included in net income, net of tax expense of $4 million in 2011, $2 million in 2010, and $7 million in 2009											(7)	(4)	(13)
Other comprehensive income, net of tax											183	78	217
Comprehensive income											1,602	1,177	1,257
Parent Company [Member]
Management fees charged to operating subsidiaries											1,272	1,175	1,057
Investment and other income, net											8	14	4
Total revenues											1,280.0	1,189.0	1,061.0
Operating costs											1,270	956	836
Depreciation											164	166	162
Interest											107	103	104
Total operating expense											1,541	1,225	1,102
Loss before income taxes and equity in net earnings of subsidiaries											(261)	(36)	(41)
(Benefit) provision for income taxes											(81)	35	(44)
(Loss) income before equity in net earnings of subsidiaries											(180)	(71)	3
Equity in net earnings of subsidiaries											1,599	1,170	1,037
Net income											1,419	1,099	1,040
Net unrealized investment gains, net of tax expense of $109 million in 2011, $47 million in 2010, and $131 million in 2009											190	82	230
Less: Reclassification adjustment for net realized gains included in net income, net of tax expense of $4 million in 2011, $2 million in 2010, and $7 million in 2009											(7)	(4)	(13)
Other comprehensive income, net of tax											183	78	217
Comprehensive income											$ 1,602	$ 1,177	$ 1,257

[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.