|**Employee Retirement Benefits**                      | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
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|**Compensation and Retirement Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Employee Retirement Benefits                          | EMPLOYEE RETIREMENT BENEFITSThe following summarizes the components of net periodic costs for our qualified and supplemental pension plans:(In millions)Three months ended June 30,Six months ended June 30,2013201220132012Service cost$3$3$6$6Interest cost3467Expected return on plan assets(4)(4)(8)(8)Amortization of actuarial loss and prior service cost3153Net periodic benefit cost$5$4$9$8See our 2012 Annual Report on Form 10-K, Item 8, Note 13, Employee Retirement Benefits, Page 130, for information on our retirement benefits. We made matching contributions of$2 millionand$3 millionto our            401(k) and Top Hat savings plans during the second quarter of 2013 and 2012 and contributions of$5 millionfor the first six months of 2013 and 2012, respectively.We contributed$15 millionto our qualified pension plan during the first quarter of 2013. We do not anticipate further contributions to our qualified pension plan during the remainder of 2013.
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|(In millions)                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
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|Service cost                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Interest cost                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Expected return on plan assets                        |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Amortization of actuarial loss and prior service cost |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Net periodic benefit cost                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

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