Employee Benefit Plans (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Percentage of bonds with highest yields excluded from calculation of yield curve for pension plan assumptions	10.00%
Percentage of bonds with lowest yields excluded from calculation of yield curve for pension plan assumptions	40.00%
Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets	7.00%	7.50%	7.75%
ERRP Reimbursement Funding	$ 5,000,000,000
Minimum Matching Employer Contribution	2,000,000
Defined Contribution Plan Employee benefit plan expense	108,000,000	120,000,000	111,000,000
Increase in year-end obligation due to change in mortality assumptions.	145,000,000
Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets 2015	6.75%
Qualified Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Fixed earnings credit given to all new participants in pension and postretirement plans	3.00%
Estimated 2015 employer contributions	$ 200,000,000
Equity Securities [Member] | Qualified Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Percentage of the fair value of total Plan assets held	69%
Fixed Income Securities | Qualified Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Percentage of the fair value of total Plan assets held	22%
Real Estate | Qualified Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Percentage of the fair value of total Plan assets held	5%
Employee Benefit Plans Other Assets [Member] | Qualified Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Percentage of the fair value of total Plan assets held	4%