Supplemental Financial Information - Components of Inventory (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Inventory, Net [Abstract]
Work in process and raw materials	$ 171	$ 133
Finished goods	206	135
Service parts	370	333
Total inventories	$ 747	$ 601

Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

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- Definition

Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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- Definition

Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date for elements of machinery or equipment held for the purpose of replacing similar parts in the course of repair or maintenance.

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The aggregate carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of items which are partially completed at the time of measurement and unprocessed items that will go through the production process and become part of the final product. This element may be used when the reporting entity combines work in process and raw materials into an aggregate amount.

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