Benefit Plans (Estimated Future Minimum Benefit Payments to Participants) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013
Pension Plans, Defined Benefit [Member]
Defined benefit plan disclosure [Line items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	$ 189
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	191
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	194
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	199
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	203
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	1,013
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined benefit plan disclosure [Line items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	5
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	4
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	5
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	4
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	4
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	$ 14