Summary of Significant Accounting Policies ( Details Textuals) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Summary Of Significant Accounting Policies Textuals [Abstract]
Line of credit facility financial covenants combined earnings and fixed charges to fixed charges ratio required	1.25
Net foreign currency transaction gains	$ 1	$ 14	$ 87
Original maturities of cash and cash equivalents	90 days or less