Retirement Plans and Postretirement Medical Benefits (Nonpension Estimated Future Benefit Payments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	$ 139,394
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	137,336
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	130,778
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	132,252
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	134,710
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	700,363
DefinedBenefitPlanExpectedFutureBenefitPayments	1,374,833
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	25,959
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	24,905
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	23,826
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	22,932
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	22,037
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	98,604
DefinedBenefitPlanExpectedFutureBenefitPayments	$ 218,263