Related Party Transactions - Related Party Revenue and Purchases (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Related Party Transaction [Line Items]
Revenues	$ 144.0	$ 161.0	$ 445.0	$ 483.0
Cost of services	966.0	987.0	2,878.0	2,823.0
Cost of hardware and software	4,182.0	4,332.0	12,727.0	12,876.0
Payment for purchase of hardware from IBM			600.0	750.0
IBM
Related Party Transaction [Line Items]
Revenues	144.0	161.0	445.0	483.0
IBM \| Hardware, software and services
Related Party Transaction [Line Items]
Cost of hardware and software	845.0	852.0	2,504.0	2,415.0
Payment for purchase of hardware from IBM			250.0	381.0
IBM \| Cost of service
Related Party Transaction [Line Items]
Cost of services	$ 114.0	$ 127.0	$ 351.0	$ 382.0

The aggregate cost of goods produced and sold and services rendered during the reporting period.

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+ Details

- Definition

Direct costs arising from transactions with related parties who are not affiliates or joint Ventures. These costs are categorized as cost of goods sold.

+ References

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+ Details

- Definition

Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

+ References

+ Details