Employee Benefit Plans And Other Postretirement Benefits (Schedule Of Obligation And Funded Status) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension and SERPA Benefits [Member]
Change in benefit obligation:
Benefit obligation, beginning of period	$ 1,714,650	$ 1,871,575
Service cost	31,498	35,987	33,681
Interest cost	86,923	79,248	83,265
Actuarial (gains) losses	309,542	(199,408)
Plan participant contributions	0	0
Benefits paid, net of Medicare Part D subsidy	(72,633)	(72,752)
Benefit obligation, end of period	2,069,980	1,714,650	1,871,575
Change in plan assets:
Fair value of plan assets, beginning of period	1,920,601	1,539,018
Actual return on plan assets	143,040	277,388
Company contributions	1,638	176,947
Plan participant contributions	0	0
Benefits paid	(72,633)	(72,752)
Fair value of plan assets, end of period	1,992,646	1,920,601	1,539,018
Funded status of the plans, December 31	(77,334)	205,951
Prepaid benefit costs (long-term assets)	0	244,871
Accrued benefit liability (current liabilities)	(1,148)	(2,549)
Accrued benefit liability (long-term liabilities)	(76,186)	(36,371)
Net amount recognized	(77,334)	205,951
Postretirement Healthcare Benefits [Member]
Change in benefit obligation:
Benefit obligation, beginning of period	366,524	403,227
Service cost	7,015	7,858	7,413
Interest cost	16,878	15,599	18,310
Actuarial (gains) losses	(2,870)	(33,729)
Plan participant contributions	2,368	2,609
Benefits paid, net of Medicare Part D subsidy	(28,909)	(29,040)
Benefit obligation, end of period	361,006	366,524	403,227
Change in plan assets:
Fair value of plan assets, beginning of period	147,875	123,106
Actual return on plan assets	8,965	24,769
Company contributions	28,048	27,849
Plan participant contributions	2,368	2,609
Benefits paid	(30,416)	(30,458)
Fair value of plan assets, end of period	156,840	147,875	123,106
Funded status of the plans, December 31	(204,166)	(218,649)
Prepaid benefit costs (long-term assets)	0	0
Accrued benefit liability (current liabilities)	(1,160)	(2,484)
Accrued benefit liability (long-term liabilities)	(203,006)	(216,165)
Net amount recognized	$ (204,166)	$ (218,649)