Global Health Care Medical Costs Payable - Activity (Details) - Accident and health insurance [Member] - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
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	13,923	16,853
Prior years	(203)	(159)
Total incurred	13,720	16,694
Paid claims related to:
Current year	11,868	14,966
Prior years	1,552	1,656
Total paid	13,420	16,622
Ending balance, net	2,228	1,928
Add: Reinsurance and other amounts recoverable	231	252
Costs payable, ending balance, gross	$ 2,459	$ 2,180