Financial Instruments - Recurring fair value measurements (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Assets
Derivatives	$ 58	$ 74
Investment securities	283	327
Liabilities
Derivatives	(27)	(82)
Fair value, measurements, recurring
Assets
Derivatives	58	74
Investment securities	283	327
Assets, fair value	341	401
Liabilities
Derivatives	(27)	(82)
Total liabilities	(27)	(82)
Fair value, measurements, recurring \| Level 1
Assets
Derivatives	0	0
Investment securities	24	39
Assets, fair value	24	39
Liabilities
Derivatives	0	0
Total liabilities	0	0
Fair value, measurements, recurring \| Level 2
Assets
Derivatives	58	74
Investment securities	0	0
Assets, fair value	58	74
Liabilities
Derivatives	(27)	(82)
Total liabilities	(27)	(82)
Fair value, measurements, recurring \| Level 3
Assets
Derivatives	0	0
Investment securities	259	288
Assets, fair value	259	288
Liabilities
Derivatives	0	0
Total liabilities	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Fair value, after the effects of master netting arrangements, of a financial asset or other 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 assets not subject to a master netting arrangement and not elected to be offset.

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-Publisher FASB
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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 portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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Fair value of financial and nonfinancial obligations.

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