Benefits Payable (Activity In Benefits Payable) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Benefits Payable [Abstract]
Balances at January 1	$ 3,214	$ 2,943	$ 2,898
Acquisitions	29	0	0
Current year, Incurred	25,821	24,186	21,944
Prior years, Incurred	(372)	(434)	(253)
Total incurred	25,449	23,752	21,691
Current year, Paid	(22,729)	(21,269)	(19,211)
Prior years, Paid	(2,548)	(2,212)	(2,435)
Total paid	(25,277)	(23,481)	(21,646)
Balances at December 31	$ 3,415	$ 3,214	$ 2,943