<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<RESTATED>
<MULTIPLIER> 1,000,000

<S>                             <C>                     <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   3-MOS                   3-MOS                   12-MOS
<FISCAL-YEAR-END>                          DEC-31-1996             DEC-31-1996             DEC-31-1996             DEC-31-1996
<PERIOD-START>                             JAN-01-1996             MAR-31-1996             JUL-01-1996             JAN-01-1996
<PERIOD-END>                               MAR-31-1996             JUN-30-1996             SEP-30-1996             DEC-31-1996
<CASH>                                             848                     963                     728                     559
<SECURITIES>                                       308                     367                     345                     253
<RECEIVABLES>                                      751                     759                     764                     676
<ALLOWANCES>                                        22                      24                      25                      20
<INVENTORY>                                        271                     261                     255                     262
<CURRENT-ASSETS>                                 2,444                   2,597                   2,406                   2,090
<PP&E>                                           5,697                   5,769                   6,098                   6,208
<DEPRECIATION>                                   1,511                   1,559                   1,607                   1,668
<TOTAL-ASSETS>                                   8,605                   8,764                   8,842                   8,512
<CURRENT-LIABILITIES>                            2,914                   2,985                   3,132                   2,883
<BONDS>                                              0                       0                       0                       0
<PREFERRED-MANDATORY>                            1,007                   1,028                       1                     603
<PREFERRED>                                          0                       0                     597                       0
<COMMON>                                             1                       1                       0                       1
<OTHER-SE>                                       (704)                   (455)                    (89)                      92
<TOTAL-LIABILITY-AND-EQUITY>                     8,605                   8,764                   8,842                   8,512
<SALES>                                          2,265                   2,540                   2,735                   9,881
<TOTAL-REVENUES>                                 2,265                   2,540                   2,735                   9,881
<CGS>                                                0                       0                       0                       0
<TOTAL-COSTS>                                    2,130                   2,166                   2,266                   8,827
<OTHER-EXPENSES>                                    47                      44                      59                     181
<LOSS-PROVISION>                                     3                       3                       3                       6
<INTEREST-EXPENSE>                                  69                      66                      66                     270
<INCOME-PRETAX>                                     88                     331                     411                     872
<INCOME-TAX>                                        34                     128                     157                     336
<INCOME-CONTINUING>                                 53                     203                     254                     536
<DISCONTINUED>                                       0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                                        53                     203                     254                     536
<EPS-PRIMARY>                                      .42                    1.95                    3.22                    5.80
<EPS-DILUTED>                                      .38                    1.73                    2.89                    5.20


</TABLE>