Employee Benefit Plans (Details) - Other Postretirement Benefit Plans, Defined Benefit [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 0	$ 1	$ 0
Interest cost	4	4	10	11
Expected return on plan assets	(2)	(2)	(5)	(5)
Amortization of prior service credit	0	0	(1)	(1)
Amortization of loss	0	0	2	1
Amortization of transition obligation	0	1	0	3
Net periodic cost	2	$ 3	7	$ 9
Expected contribution to postretirement benefit plan in current year			7
Total contribution to the plan during the period	$ 2		$ 6