Restructuring Actions and Exit Activities - Roll Forward (Details) - 2018 Restructuring Actions - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Restructuring Reserve Roll Forward
Restructuring actions balances, Beginning Balance	$ 84	$ 137
Non-cash changes		(12)
Cash payments	(13)	(24)
Adjustments	(1)	(17)
Restructuring actions balances, Ending Balance	70	84
Employee-Related
Restructuring Reserve Roll Forward
Restructuring actions balances, Beginning Balance	84	125
Cash payments	(13)	(24)
Adjustments	(1)	(17)
Restructuring actions balances, Ending Balance	70	84
Asset-Related
Restructuring Reserve Roll Forward
Restructuring actions balances, Beginning Balance		12
Non-cash changes		$ (12)
Adjustments

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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- Definition

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

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- Definition

Amount of expense (reversal of expense) which increases (decreases) the restructuring reserve from an adjustment to a previously accrued restructuring liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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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Amount of decrease in the reserve for full or partial settlement through consideration other than cash.

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