Relationship with IBM and Related Party Transactions - Tax Sharing Agreement (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Relationship with IBM and Related Party Transactions
Provision for/(benefit from) income taxes	$ (13)	$ 150
Effective rate on continuing operations	(10.10%)	77.50%
Discrete tax benefit	$ 40
Additional provisional charge (benefit) resulting from guidance related to U.S. tax reform		$ 116

The net benefit amount from the recognition of a deferred tax asset.

No definition available.

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- Definition

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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- References

No definition available.

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- Definition

Amount of income tax expense (benefit) for measurement period adjustment from accounting for tax effect pursuant to Tax Cuts and Jobs Act.

+ References

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