Employee Benefits (Details 1) (Other Postretirement Benefit Plans, Defined Benefit [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Other Postretirement Benefit Plans, Defined Benefit [Member]
Net postretirement benefit cost for all funded and unfunded plans
Interest cost on APBO	$ 1	$ 1	$ 2	$ 2
Expected return on plan assets	(1)	(1)	(2)	(2)
Net pension cost