Derivative financial instruments and risk management (Details 6) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Offsetting Liabilities
Derivative Asset, Collateral, Obligation to Return Cash, Offset	$ 0
Gross Amount of Recognized Liabilities	(150)	$ (93)
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amount of Liabilities Presented in the Statement of Financial Position	(150)	(93)
Financial Instruments	53	32
Cash Collateral Pledged	0	0
Net Amount of Liabilities	97	61
Machinery, Energy & Transportation
Offsetting Liabilities
Gross Amount of Recognized Liabilities	(87)	(25)
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amount of Liabilities Presented in the Statement of Financial Position	(87)	(25)
Financial Instruments	19	22
Cash Collateral Pledged	0	0
Net Amount of Liabilities	68	3
Financial Products
Offsetting Liabilities
Gross Amount of Recognized Liabilities	(63)	(68)
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amount of Liabilities Presented in the Statement of Financial Position	(63)	(68)
Financial Instruments	34	10
Cash Collateral Pledged	0	0
Net Amount of Liabilities	$ 29	$ 58

Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

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Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Fair value, after effects of master netting arrangements, deduction of liabilities not subject to a master netting arrangement and elected not to be offset, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, offset against the right to receive collateral.

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Fair value of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be offset, deducted from derivative liabilities.

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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.

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