Employee Benefit Plans (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Pension Plans [Member]
Components of net periodic benefit cost
Interest cost	$ 25	$ 27	$ 27
Expected return on plan assets	(31)	(31)	(28)
Recognized net actuarial loss (gain)	13	5	2
Net periodic benefit cost (gain)	7	1	1
Post-Retirement Benefit Plans [Member]
Components of net periodic benefit cost
Interest cost		1	1
Amortization of prior service cost		(4)	(6)
Recognized net actuarial loss (gain)	(4)	(1)	(1)
Net periodic benefit cost (gain)	$ (4)	$ (4)	$ (6)