Long-term Commitments (Operating Lease Agreements) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Long-Term Commitments [Abstract]
2013, Gross Rental Commitments	$ 404
2014, Gross Rental Commitments	359
2015, Gross Rental Commitments	315
2016, Gross Rental Commitments	279
2017, Gross Rental Commitments	236
Subsequent years, Gross Rental Commitments	1,227
2013, Rentals from Subleases	49
2014, Rentals from Subleases	48
2015, Rentals from Subleases	43
2016, Rentals from Subleases	42
2017, Rentals from Subleases	40
Subsequent years, Rentals from Subleases	109
2013, Net Rental Commitments	355
2014, Net Rental Commitments	311
2015, Net Rental Commitments	272
2016, Net Rental Commitments	237
2017, Net Rental Commitments	196
Subsequesnt years, Net Rental Commitments	$ 1,118

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Amount of minimum sublease rentals to be received by the seller-lessee after the fifth fiscal year following the latest fiscal year for sale-leaseback transactions accounted for using the deposit method or as a financing.

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Amount of minimum sublease rentals to be received by the seller-lessee in the fourth fiscal year following the latest fiscal year for sale-leaseback transactions accounted for using the deposit method or as a financing.

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Amount of minimum sublease rentals to be received by the seller-lessee in the next fiscal year following the latest fiscal year for sale-leaseback transactions accounted for using the deposit method or as a financing.

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Amount of minimum sublease rentals to be received by the seller-lessee in the third fiscal year following the latest fiscal year for sale-leaseback transactions accounted for using the deposit method or as a financing.

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Amount of minimum sublease rentals to be received by the seller-lessee in the second fiscal year following the latest fiscal year for sale-leaseback transactions accounted for using the deposit method or as a financing.

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Amount of required minimum rental payments maturing in the next fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the forth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the third fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the second fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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