Income Taxes (Details 3) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Unrecognized Tax Benefits Rollforward (Table Amounts) [Abstract]
Unrecognized tax benefits at beginning of the year	$ 283	$ 135	$ 223
Additions based on tax positions related to the current year	293	102	35
Additions for tax positions of prior years	207	110	2
Reductions for tax positions of prior years	(23)	(44)	(40)
Settlements with taxing authorities	(7)	(20)	(84)
Other, net	(5)	0	(1)
Net change in unrecognized tax benefits	465	148	(88)
Unrecognized tax benefits at end of the year	$ 748	$ 283	$ 135

Unrecognized Tax Benefits, Other

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- Definition

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

+ References

No definition available.

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- Definition

Amount of unrecognized tax benefits.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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-Name Accounting Standards Codification
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- Definition

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 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 increase (decrease) in unrecognized tax benefits attributable to uncertain tax positions taken in tax returns.

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