Leases - Supplemental cash flow and other information (Details) $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 309
Operating cash flows from finance leases	2
Financing cash flows from finance leases	18
Right of use assets obtained in exchange for lease liabilities:
Operating leases	326
Finance leases	61
Gain on sale leaseback transactions, net	$ 82

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Amount of interest paid on finance lease liability.

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Amount of cash outflow for principal payment on finance lease.

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Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.

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Amount of increase in right-of-use asset obtained in exchange for finance lease liability.

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Amount of increase in right-of-use asset obtained in exchange for operating lease liability.

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Amount of gain (loss) on sale and leaseback transaction from transfer of asset accounted for as sale.

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