Other Comprehensive Income (Loss) (Components And Allocated Tax Effects Of Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other Comprehensive Income (Loss) [Abstract]
Unrealized loss on available-for-sale securities Before-Tax	$ 34		$ 13	$ 5	$ (203)
Unrealized gain (loss) on hedging activities, Before-Tax	4,215		(111,333)	44,371	(236,147)
Other Comprehensive Income (Loss), Finalization of Pension and Non-Pension Postretirement Plan Valuation, before Tax				28,986
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax				1,726
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	8,600	30,900			7,102
Other comprehensive income (loss), Before-Tax	4,249		(111,320)	75,088	(229,248)
Less other comprehensive income attributable to noncontrolling interest, Before-Tax	(665)		129	2,068	529
Other Comprehensive Income (Loss), before Tax, Current Year Portion Attributable to Parent	4,914		(111,449)	73,020	(229,777)
Unrealized loss on available-for-sale securities, Tax Expense (Benefit)	13		6	2	(78)
Unrealized gain on hedging activities, Tax Expense (Benefit)	1,933		(43,359)	16,473	(92,068)
Other Comprehensive Income (Loss), Finalization of Pension and Non-Pension Postretirement Plan Valuation, Tax				11,275
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax				671	2,763
Other comprehensive income, Tax Expense (Benefit)	1,946		(43,353)	28,421	(89,383)
Less other comprehensive income attributable to noncontrolling interest, Tax Expense (Benefit)	0		0	0	0
Other Comprehensive Income (Loss), Tax, Components	1,946		(43,353)	28,421	(89,383)
Unrealized loss on available-for-sale securities, After-Tax	21		7	3	(125)
Unrealized gain on hedging activities, After-Tax	2,282		(67,974)	27,898	(144,079)
Other Comprehensive Income (Loss), Finalization of Pension and Non-Pension Postretirement Plan Valuation, Net of Tax				17,711
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	1,700			1,055	4,339
Other comprehensive income (loss)	2,303		(67,967)	46,667	(139,865)
Less other comprehensive income attributable to noncontrolling interest, After-Tax	(665)		129	2,068	529
Other Comprehensive Income (Loss), Net of Tax, Components	$ 2,968		$ (68,096)	$ 44,599	$ (140,394)