Global Health Care Medical Costs Payable (Tables) (Global Health Benefits Segment [Member])
 3 Months Ended
Mar. 31, 2015
Global Health Benefits Segment [Member]
  
Liability For Unpaid Claims And Claims Adjustment Expense [Line Items]  
Schedule of medical costs payable balance
 March 31,December 31,
(In millions)20152014
Incurred but not yet reported$ 1,830$ 1,777
Reported claims in process  439  288
Physician incentives and other medical care expenses and services payable  139  115
Medical costs payable$ 2,408$ 2,180
Schedule of medical costs payable activity
 For the period ended
 March 31,December 31,
(In millions)20152014
Balance at January 1,$ 2,180$ 2,050
Less: Reinsurance and other amounts recoverable  252  194
Balance at January 1, net  1,928  1,856
Incurred costs related to:    
Current year  4,713  16,853
Prior years  (109)  (159)
Total incurred  4,604  16,694
Paid costs 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
Ending Balance$ 2,408$ 2,180