Employee Benefit Plans And Other Postretirement Benefits (Schedule Of Obligation And Funded Status) (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	12 Months Ended
	Jan. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Balance, end of period		$ 109,160	$ 1,253,916
Pension And SERPA Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation, beginning of period	1,871,575	1,570,930	1,390,374
Service cost		33,681	37,341	42,889
Interest cost		83,265	80,805	77,996
Actuarial losses (gains)		276,069	127,259
Plan participant contributions		1,459	3,441
Early Retirement Reinsurance Program Proceeds		0	0
Benefits paid, net of Medicare Part D subsidy		(93,829)	(68,525)
Net curtailments and settlements		0	235
Benefit obligation, end of period		1,871,575	1,570,930	1,390,374
Balance, beginning of period	1,539,018	1,253,916	1,105,487
Actual return on plan assets		160,731	8,129
Company contributions	175,000	216,741	205,383
Plan participant contributions		1,459	3,441
Benefits paid		(93,829)	(68,524)
Balance, end of period		1,539,018	1,253,916	1,105,487
Funded status of the plans, December 31		(332,557)	(317,014)
Accrued benefit liability (other current liabilities)		2,263	14,531
Accrued benefit liability (other long-term liabilities)		330,294	302,483
Net amount recognized		332,557	317,014
Postretirement Healthcare Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation, beginning of period		380,625	378,341
Service cost		7,413	7,630	9,957
Interest cost		18,310	19,644	20,774
Actuarial losses (gains)		23,367	(1,364)
Plan participant contributions		1,561	1,527
Early Retirement Reinsurance Program Proceeds		0	2,249
Benefits paid, net of Medicare Part D subsidy		(28,049)	(27,402)
Net curtailments and settlements		0	0
Benefit obligation, end of period		403,227	380,625	378,341
Balance, beginning of period		109,160	121,064
Actual return on plan assets		13,946	820
Company contributions		27,675	14,111
Plan participant contributions		1,561	1,527
Benefits paid		(29,236)	(28,362)
Balance, end of period		123,106	109,160	121,064
Funded status of the plans, December 31		(280,121)	(271,465)
Accrued benefit liability (other current liabilities)		2,059	2,883
Accrued benefit liability (other long-term liabilities)		278,062	268,582
Net amount recognized		$ 280,121	$ 271,465