Postretirement Benefit Plans (Details Textual) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block
Other Postretirement Benefit Expense	$ 1	$ 2	$ 2	$ 3
Amortization of net actuarial loss (less than $1 million for the three and six months ended June 30, 2015)	$ (1)	$ (1)	(1)	(1)
Employer contribution to defined benefit plan			13	$ 22
Minimum
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block
Additional contributions			11
Maximum
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block
Additional contributions			$ 21