Employee Benefit Plans And Other Postretirement Benefits (Schedule Of Fair Value Of Postretirement Healthcare Plan Assets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	$ 89,909	$ 846,677
Total fixed-income holdings	17,393	358,953
Total postretirement healthcare plan assets	109,160	1,253,916
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	89,456	801,150
Total fixed-income holdings	7,237	223,683
Total postretirement healthcare plan assets	96,693	1,024,833
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	453	3,400
Total fixed-income holdings	10,156	135,270
Total postretirement healthcare plan assets	12,467	186,956
Cash And Cash Equivalents [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total postretirement healthcare plan assets	1,858	48,286
Cash And Cash Equivalents [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total postretirement healthcare plan assets	0	0
Cash And Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total postretirement healthcare plan assets	1,858	48,286
U.S. Companies [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	79,544	533,030
U.S. Companies [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	79,091	529,630
U.S. Companies [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	453	3,400
Foreign Companies [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	10,365	55,555
Foreign Companies [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	10,365	55,555
Foreign Companies [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	0	0
Pooled Equity Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings		166,460
Pooled Equity Funds [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings		166,460
Pooled Equity Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings		0
U.S. Treasuries [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	7,237	50,715
U.S. Treasuries [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	7,237	50,715
U.S. Treasuries [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	0	0
Federal Agencies [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	4,172	51,290
Federal Agencies [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	0	0
Federal Agencies [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	4,172	51,290
Corporate Bonds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	5,537	77,295
Corporate Bonds [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	0	0
Corporate Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	5,537	77,295
Foreign Bonds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	307	6,312
Foreign Bonds [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	0	0
Foreign Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	307	6,312
Municipal Bonds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	140	373
Municipal Bonds [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	0	0
Municipal Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	140	373
Postretirement Healthcare Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total postretirement healthcare plan assets	123,106	109,160	121,064
Postretirement Healthcare Benefits [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total postretirement healthcare plan assets	107,270
Postretirement Healthcare Benefits [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total postretirement healthcare plan assets	15,836
Postretirement Healthcare Benefits [Member] | Cash And Cash Equivalents [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total postretirement healthcare plan assets	5,522
Postretirement Healthcare Benefits [Member] | Cash And Cash Equivalents [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total postretirement healthcare plan assets	0
Postretirement Healthcare Benefits [Member] | Cash And Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total postretirement healthcare plan assets	5,522
Postretirement Healthcare Benefits [Member] | U.S. Companies [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	60,658
Postretirement Healthcare Benefits [Member] | U.S. Companies [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	60,658
Postretirement Healthcare Benefits [Member] | U.S. Companies [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	0
Postretirement Healthcare Benefits [Member] | Foreign Companies [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	13,625
Postretirement Healthcare Benefits [Member] | Foreign Companies [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	13,625
Postretirement Healthcare Benefits [Member] | Foreign Companies [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	0
Postretirement Healthcare Benefits [Member] | Pooled Equity Funds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	27,617
Postretirement Healthcare Benefits [Member] | Pooled Equity Funds [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	27,617
Postretirement Healthcare Benefits [Member] | Pooled Equity Funds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	0
Postretirement Healthcare Benefits [Member] | Total Fixed Income Holdings [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	101,900
Total fixed-income holdings	15,684
Postretirement Healthcare Benefits [Member] | Total Fixed Income Holdings [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	101,900
Total fixed-income holdings	5,370
Postretirement Healthcare Benefits [Member] | Total Fixed Income Holdings [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total equity holdings	0
Total fixed-income holdings	10,314
Postretirement Healthcare Benefits [Member] | U.S. Treasuries [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	5,370
Postretirement Healthcare Benefits [Member] | U.S. Treasuries [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	5,370
Postretirement Healthcare Benefits [Member] | U.S. Treasuries [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	0
Postretirement Healthcare Benefits [Member] | Federal Agencies [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	3,489
Postretirement Healthcare Benefits [Member] | Federal Agencies [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	0
Postretirement Healthcare Benefits [Member] | Federal Agencies [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	3,489
Postretirement Healthcare Benefits [Member] | Corporate Bonds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	6,033
Postretirement Healthcare Benefits [Member] | Corporate Bonds [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	0
Postretirement Healthcare Benefits [Member] | Corporate Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	6,033
Postretirement Healthcare Benefits [Member] | Foreign Bonds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	659
Postretirement Healthcare Benefits [Member] | Foreign Bonds [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	0
Postretirement Healthcare Benefits [Member] | Foreign Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	659
Postretirement Healthcare Benefits [Member] | Municipal Bonds [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	133
Postretirement Healthcare Benefits [Member] | Municipal Bonds [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	0
Postretirement Healthcare Benefits [Member] | Municipal Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fixed-income holdings	$ 133