Basis of Presentation Medicare Part D (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Other current receivables, net	$ 2,255	$ 1,643
Other Policyholder Funds	5,063	3,979
CMS Subsidies [Member]
Other current receivables, net	0	0
Other Policyholder Funds	70	475
Drug Discount [Member]
Other current receivables, net	509
Other Policyholder Funds	649
Risk-Share [Member]
Other current receivables, net	0	0
Other Policyholder Funds	$ 170	$ 265