Leases (Components of Lease Expense) (Details) - USD ($) $ in Millions |
12 Months Ended | |
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Dec. 31, 2020 |
Dec. 31, 2019 |
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| Leases [Abstract] | ||
| Operating lease cost | $ 5,896 | $ 5,684 |
| Finance lease cost: | ||
| Amortization of right-of-use assets | 287 | 271 |
| Interest on lease obligation | 156 | 169 |
| Total finance lease cost | $ 443 | $ 440 |
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- Definition Finance Lease, Cost No definition available.
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- Definition Amount of interest expense on finance lease liability. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of amortization expense attributable to right-of-use asset from finance lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- References No definition available.
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- References No definition available.
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- Definition Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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