Employee Benefit Plans (Narrative) (Details) (USD $)	6 Months Ended
	Jun. 30, 2013
Defined Benefit Plan Disclosure [Line Items]
Reduction in pension benefit obligation from remeasurement and curtailments	$ 354,000,000
Reduction in accumulated postretirement benefit obligation	78,000,000
Reduction in net periodic benefit cost for 2013	36,000,000
Contributions to defined benefit pension plans and OPEB plans	0
Expected contribution to voluntary employees' beneficiary association	$ 12,000,000
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.80%
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.70%