<ARTICLE>                     5
<LEGEND>
     This  schedule  contains  summary  financial   information  extracted  from
     Consolidated  Summary Financial  Statements and Notes included in this Form
     10-Q and is  qualified  in its  entirety  by  reference  to such  financial
     statements.
</LEGEND>
<MULTIPLIER>                                 1,000
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>               DEC-31-1998
<PERIOD-START>                  JAN-01-1998
<PERIOD-END>                    JUN-30-1998
<CASH>                                      47,800
<SECURITIES>                               385,200
<RECEIVABLES>                              160,500
<ALLOWANCES>                                     0
<INVENTORY>                                192,800
<CURRENT-ASSETS>                           872,400
<PP&E>                                   2,254,200
<DEPRECIATION>                          (1,197,200)
<TOTAL-ASSETS>                           2,948,400
<CURRENT-LIABILITIES>                      405,500
<BONDS>                                    598,700
<PREFERRED-MANDATORY>                            0
<PREFERRED>                                      0
<COMMON>                                   117,000
<OTHER-SE>                               1,331,400
<TOTAL-LIABILITY-AND-EQUITY>             2,948,400
<SALES>                                  1,171,500
<TOTAL-REVENUES>                         1,171,500
<CGS>                                    1,002,200
<TOTAL-COSTS>                              848,800
<OTHER-EXPENSES>                                 0
<LOSS-PROVISION>                                 0
<INTEREST-EXPENSE>                          19,800
<INCOME-PRETAX>                            302,900
<INCOME-TAX>                               126,300
<INCOME-CONTINUING>                        178,800
<DISCONTINUED>                                   0
<EXTRAORDINARY>                                  0
<CHANGES>                                        0
<NET-INCOME>                               178,800
<EPS-PRIMARY>                                 1.64
<EPS-DILUTED>                                 1.64