|**Comprehensive Income (Tables)**                              | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
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|**Comprehensive Income [Abstract]**                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Components of accumulated other comprehensive loss, net of tax | The components of accumulated other comprehensive loss, net of tax are as follows:September 30,December 31,($ in thousands)20122011Pension costs$552,895$575,163Postretirement costs43,70941,811Deferred taxes on pension and OPEB costs(221,931)(230,161)All other148150$374,821$386,963                                                                                                                                                                                                                                                                                                                                                                                                                                                 
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|($ in thousands)                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
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|Pension costs                                                  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Postretirement costs                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Deferred taxes on pension and OPEB costs                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|All other                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
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|Other comprehensive income (loss)                              | Our other comprehensive income for the three and nine months ended September 30, 2012 and 2011 is as follows:For the three months ended September 30,20122011Before-TaxTax Expense/Net-of-TaxBefore-TaxTax Expense/Net-of-Tax($ in thousands)Amount(Benefit)AmountAmount(Benefit)AmountAmortization of pension and postretirement costs -other comprehensive income$6,080$3,772$2,308$3,334$-$3,334For the nine months ended September 30,20122011Before-TaxTax Expense/Net-of-TaxBefore-TaxTax Expense/Net-of-TaxAmount(Benefit)AmountAmount(Benefit)AmountAmortization of pension and postretirement costs$20,370$8,228$12,142$10,003$1,199$8,804All other---(480)-(480)Other comprehensive income$20,370$8,228$12,142$9,523$1,199$8,324
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|($ in thousands)                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
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|Amortization of pension and postretirement costs -             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|other comprehensive income                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
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|Amortization of pension and postretirement costs               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|All other                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Other comprehensive income                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
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