Capital Preferred Stock (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Class of Stock [Line Items]
Preferred Stock, Value, Outstanding	$ 1,225	$ 1,225	$ 725
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Value, Outstanding	172	172	172
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Value, Outstanding	103	103	103
Series E Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Value, Outstanding	450	450	450
Series F Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Value, Outstanding	$ 500	$ 500	$ 0