Significant Accounting Policy Accumulated Other Comprehensive Income (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications, net of tax, related to discontinued operations	$ 258,250
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	121,521,000	42,493,000
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(28,753,000)	(133,889,000)	(310,743,000)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	10,465,000	53,990,000	121,484,000
Defined Benefit Plan, Actuarial Net (Gains) Losses	46,155,000	86,481,000	106,299,000
Curtailment Gain/Loss - Deferred Tax	(36,182,000)	0	0
Net periodic (benefit) cost	16,687,000	93,799,000	52,446,000
Actuarially Determined Long-Term Liability Tax Expense	(6,139,000)	(35,806,000)	(19,720,000)
Defined Benefit Plan, Service Cost	(22,381,000)	(32,164,000)	(53,853,000)
Actuarially Long-Term Liabilities Net of Tax	10,548,000	57,993,000	32,726,000
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	(272,621,000)	(367,610,000)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(151,100,000)	(325,117,000)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	181,757,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(7,740,000)
Other Comprehensive Income (Loss), Net of Tax	174,017,000	422,225,000	54,212,000
Commodity Contract [Member] | Cash Flow Hedging [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Derivative Instruments, Gain Reclassified from Accumulated OCI into Income, Effective Portion	(18,288,000)	(79,899,000)	(189,259,000)
Pension Plan, Defined Benefit [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Defined Benefit Plan, Actuarial Net (Gains) Losses	136,995,000	(82,718,000)
Defined Benefit Plan, Net Periodic Benefit Cost	29,095,000	(39,482,000)	0
Net periodic (benefit) cost	52,406,000	81,230,000	58,099,000
Defined Benefit Plan, Service Cost	(1,217,000)	(1,611,000)	(1,630,000)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	331,500,000	282,008,000
Postretirement Benefit Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	84,441,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	10,548,000
Other Comprehensive Income (Loss), Net of Tax	94,989,000
Cash Flow Hedging [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	97,316,000
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(18,288,000)
Other Comprehensive Income (Loss), Net of Tax	$ 79,028,000