Restructuring of Operations - Additional Information (Details) $ in Millions			3 Months Ended	9 Months Ended
Sep. 30, 2019 employee	Jan. 01, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Restructuring and Related Activities [Abstract]
Restructuring charges			$ 5	$ 9	$ 23	$ 17
Reclassification of accrued lease cease-use costs after adopting new leasing standard		$ 4			$ (4)
Estimated reduction of employees \| employee	200

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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