Pension Plans And Other Postretirement Benefit Plans (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined benefit pension plan	$ (44,000,000)	$ (26,000,000)	$ (21,000,000)
Amortization of transition obligation	34,500,000
Amortization of transition obligation period	20 years
Percentage point increases in accumulated postretirement benefit obligation	20,800,000
Percentage point increase in service and interest cost	1,400,000
Percentage point decrease in accumulated postretirement benefit obligation	16,700,000
Percentage point decrease in service and interest cost	1,100,000
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined benefit pension plan	44,000,000	26,000,000
Expected contributions to pension plan	44,000,000
Amortization of transition obligation	0	0	0
Other Post-Retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions to defined benefit pension plan	0	0
Expected contributions to pension plan	6,100,000
Amortization of transition obligation	$ 505,000	$ 505,000	$ 505,000
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation of equity securities	51.00%	51.00%
Equity Securities [Member] | Other Post-Retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation of equity securities	62.00%	62.00%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation of equity securities	31.00%	31.00%
Debt Securities [Member] | Other Post-Retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation of equity securities		38.00%