Global Health Care Medical Costs Payable - Activity (Details) (Accident and health insurance [Member], USD $)
In Millions, unless otherwise specified
3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Accident and health insurance [Member]
   
Medical Claims Payable Activity [Abstract]    
Costs payable, beginning balance, gross $ 2,180 $ 2,050
Less: Reinsurance and other amounts recoverable 252 194
Balance at January 1, net 1,928 1,856
Incurred claims related to:    
Current year 4,713 16,853
Prior years (109) (159)
Total incurred 4,604 16,694
Paid claims related to:    
Current year 3,025 14,966
Prior years 1,343 1,656
Total paid 4,368 16,622
Ending balance, net 2,164 1,928
Add: Reinsurance and other amounts recoverable 244 252
Costs payable, ending balance, gross $ 2,408 $ 2,180