Income Taxes 3 (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance, January 1	$ 24	$ 308	$ 211
Increases:
Current year tax positions	4	8	79
Tax positions related to prior years	46	0	24
Decreases:
Tax positions related to prior years	0	(289)	(1)
Settlements with tax authorities	0	0	(1)
Lapse of statute of limitations	(1)	(3)	(4)
Balance, December 31	$ 73	$ 24	$ 308

Decrease in unrecognized tax benefits excluding amounts pertaining to examined tax returns.

No definition available.

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- Definition

Increase in unrecognized tax benefits excluding amounts pertaining to examined tax returns.

+ References

No definition available.

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

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