Medicare Part D Pharmacy Benefits Contract Medicare Part D Pharmacy Benefits Contract table (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Other Receivables, Net, Current	$ 2,145	$ 2,255
Other Policyholder Funds	4,843	5,063
CMS Subsidies [Member]
Other Receivables, Net, Current	0	0
Other Policyholder Funds	85	70
Drug Discount [Member]
Other Receivables, Net, Current	371	509
Other Policyholder Funds	487	649
Risk-Share [Member]
Other Receivables, Net, Current	0	0
Other Policyholder Funds	$ 259	$ 170