Medical Costs Reserve Development (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Related to Prior Years	$ 100	$ 120	$ 230	$ 380
Related to Current Years	$ 50	$ 150