Income Taxes - Reconciliation of the beginning and ending amount of unrecognized tax benefits (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Reconciliation of the Company's beginning and ending amount of unrecognized tax benefits
Balance at the beginning of the period	$ 280	$ 278
Additions based on tax positions related to the current year	18	25
Additions for tax positions of prior years	10	12
Reductions for tax positions of prior years	(24)	(26)
Settlements	0	(6)
Business combinations	1	0
Lapse of statute of limitations	(6)	(7)
Foreign currency translation, increase	0	4
Balance at the end of the period	$ 279	$ 280

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of unrecognized tax benefits.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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- Definition

Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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- Definition

Amount of increase in unrecognized tax benefits resulting from acquisitions.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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