Employee Benefit Plans (Details) - Other Postretirement Benefit Plans, Defined Benefit [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1	$ 0	$ 1	$ 0
Interest cost	3	3	6	7
Expected return on plan assets	(1)	(2)	(3)	(3)
Amortization of prior service credit	(1)	(1)	(1)	(1)
Amortization of loss	1	1	2	1
Amortization of transition obligation	0	1	0	2
Net periodic cost	3	$ 2	5	$ 6
Expected contribution to postretirement benefit plan in current year			7
Total contribution to the plan during the period	$ 2		$ 4