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