|**Operating Leases, Commitments and Contingencies, and Guarantees (Tables)**   | 12 Months Ended                                                                                                                                                                                                                   
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|**Operating Leases, Commitments and Contingencies, and Guarantees [Abstract]** |                                                                                                                                                                                                                                   
|Future minimum lease payments                                                  | The table below presents the future minimum lease payments to be made under non-cancelable operating leases as ofDecember 31, 2015.(In millions)Future Minimum Lease Payments2016$35201731201830201925202023Thereafter117Total$261
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|                                                                               |                                                                                                                                                                                                                                   
|(In millions)                                                                  | Future Minimum Lease Payments                                                                                                                                                                                                     
|2016                                                                           | $                                                                                                                                                                                                                                 
|2017                                                                           | 31                                                                                                                                                                                                                                
|2018                                                                           | 30                                                                                                                                                                                                                                
|2019                                                                           | 25                                                                                                                                                                                                                                
|2020                                                                           | 23                                                                                                                                                                                                                                
|Thereafter                                                                     | 117                                                                                                                                                                                                                               
|Total                                                                          | $                                                                                                                                                                                                                                 

X- DefinitionOperating Leases, Commitments and Contingencies, and Guarantees
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duration X- DefinitionTabular disclosure of future minimum payments required in the aggregate and for each of the five succeeding fiscal years for operating leases having initial or remaining noncancelable lease terms in excess of one year and the total minimum rentals to be received in the future under noncancelable subleases as of the balance sheet date.
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