Benefit Plans (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Amounts charged to expense for defined contribution plans	$ 80,000,000	$ 81,000,000	$ 106,000,000
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	6,800,000,000	7,500,000,000
Projected benefit obligation	299,000,000
Accumulated benefit obligation	261,000,000
Fair value of plan assets	66,000,000
Estimated net loss expected to be amortized from accumulated other comprehensive losses during 2014	153,000,000
Estimated prior service cost ( credit) expected to be amortized from accumulated other comprehensive losses during 2014	10,000,000
Benefit obligation	7,137,000,000	7,924,000,000	6,965,000,000
Employer contributions	393,000,000	557,000,000
Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated net loss expected to be amortized from accumulated other comprehensive losses during 2014	29,000,000
Estimated prior service cost ( credit) expected to be amortized from accumulated other comprehensive losses during 2014	(43,000,000)
Benefit obligation	2,317,000,000	2,663,000,000	2,505,000,000
Emerging Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Composition of plan assets	3.00%
Corporate Bond Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Composition of plan assets	26.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation percentage of equity securities	55.00%
Composition of plan assets	60.00%
Equity Securities [Member] | Emerging Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Composition of plan assets	4.00%
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation percentage of equity securities	45.00%
US Treasury And Foreign Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Composition of plan assets	7.00%
Other than Securities Investment [Member]
Defined Benefit Plan Disclosure [Line Items]
Composition of plan assets	7.00%
Minimum [Member] | Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to its pension plan in 2014	20,000,000
Maximum [Member] | Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions to its pension plan in 2014	50,000,000
Other Current Liabilities [Member] | Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	$ 162,000,000	$ 159,000,000
Below grade investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Composition of plan assets	7.00%
Below grade investments [Member] | Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Composition of plan assets	18.00%