Leases - Components of Lease Costs (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
ROU assets			$ 200
Lease liabilities	$ 155	$ 155	$ 200
Components of lease cost
Finance lease cost	7	14
Operating lease cost	423	1,243
Short-term lease cost	11	26
Variable lease cost	90	345
Sublease income	(7)	(16)
Total lease cost	$ 523	$ 1,613
Real estate
Lessee, Lease, Description [Line Items]
Average term (in years)	5 years	5 years
Equipment leases \| Minimum
Lessee, Lease, Description [Line Items]
Average term (in years)	2 years	2 years
Equipment leases \| Maximum
Lessee, Lease, Description [Line Items]
Average term (in years)	5 years	5 years
Property, plant and equipment
Lessee, Lease, Description [Line Items]
ROU assets	$ 140	$ 140
Short-term debt
Lessee, Lease, Description [Line Items]
Lease liabilities	34	34
Long-term debt
Lessee, Lease, Description [Line Items]
Lease liabilities	$ 121	$ 121

Amount of finance lease cost recognized by lessee for lease contract.

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- Definition

Present value of lessee's discounted obligation for lease payments from finance lease.

+ References

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- Definition

Amount of lessee's right to use underlying asset under finance lease.

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Amount of lease cost recognized by lessee for lease contract.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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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.

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- Definition

Amount of short-term lease cost, excluding expense for lease with term of one month or less.

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- Definition

Amount of sublease income excluding finance and operating lease expense.

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- Definition

Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases.

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