Employee Benefits Assets and Liabilities associated with Non-qualified benefit plans (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Non-qualified benefit plan trust	$ 35	$ 32
Non-qualified benefit plan liabilities	101	102
Total Non-qualified benefit plan trust assets [Domain]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Non-qualified benefit plan trust	35	32
Non-qualified benefit plan liabilities	101	102
Non Qualified Benefit Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Non-qualified benefit plan trust	16	15
Non-qualified benefit plan liabilities	22	25
Other non-qualified benefit plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Non-qualified benefit plan trust	19	17
Non-qualified benefit plan liabilities	$ 79	$ 77