Derivative and Other Financial Instruments (Schedule of Offsetting Derivative Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Derivative assets
Derivative assets	$ 42	$ 22
Gross amounts recognized in the Balance Sheet	42	22
Gross amounts not offset in the Balance Sheet	9	4
Net amount	33	18
Derivative liabilities
Derivative liabilities	52	45
Gross amounts recognized in the Balance Sheet	52	45
Gross amounts not offset in the Balance Sheet	9	4
Net amount	$ 43	$ 41