Fair Value of Financial Instruments (Details 1) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	$ 342	$ 321
Available-for-sale Securities	10	7
Derivative Assets (Liabilities), at Fair Value, Net	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	1	2
Available-for-sale Securities	0	0
Derivative Assets (Liabilities), at Fair Value, Net	0	8
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	343	323
Available-for-sale Securities	10	7
Derivative Assets (Liabilities), at Fair Value, Net	$ 0	$ 8