Global Health Care Medical Costs Payable (Details) - Accident and health insurance [Member] - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Liability For Unpaid Claims And Claims Adjustment Expense [Line Items]
Incurred but not yet reported	$ 1,757	$ 1,777
Reported claims in process	470	288
Phyician incentives and other medical expense payable	128	115
Medical costs payable	$ 2,355	$ 2,180	$ 2,050	$ 1,856