Medicare Part D Pharmacy Benefits (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Other current receivables	$ 5,189	$ 3,998
Other policy liabilities	5,792	5,279
CMS Subsidies [Member]
Other current receivables	1,626	881
Other policy liabilities	0	0
Drug Discount [Member]
Other current receivables	592	425
Other policy liabilities	313	152
Risk-Share [Member]
Other current receivables	0	0
Other policy liabilities	$ 165	$ 214