Long-Term Debt (Details 1) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Summary showing division of total long-term debt
Obligations secured by real estate	$ 0	$ 59
Long-term debt	1,020	1,061
Senior unsecured obligations [Member]
Summary showing division of total long-term debt
Unsecured obligations	720	852
Subordinated unsecured obligations [Member]
Summary showing division of total long-term debt
Unsecured obligations	$ 300	$ 150