Benefit Plans (Changes in Benefit Obligations of Postemployment Plans) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Compensation and Retirement Disclosure [Abstract]
Accrued postemployment costs at beginning of year	$ 149	$ 270
Service cost	1	1	1
Interest cost	1	1	2
Benefits paid	(65)	(143)
Actuarial (gains) losses and assumption changes	(4)	27
Other	(17)	(7)	121
Accrued postemployment costs at beginning of year	$ 65	$ 149	$ 270