Reorganization and Business Transformation - Costs Incurred For Reorganization Plan (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring reserve. beginning balance	$ 12
Expense accruals	8
Cash payments	(19)	$ (11)
Restructuring reserve. ending balance	1	12
Employee separation benefits costs related to headquarter transition and business transformation
Restructuring Cost and Reserve [Line Items]
Restructuring reserve. beginning balance	11
Expense accruals	5
Cash payments	(15)
Restructuring reserve. ending balance	1	11
Transition support and other exit related costs for the headquarter transition and business transformation
Restructuring Cost and Reserve [Line Items]
Restructuring reserve. beginning balance	1
Expense accruals	3
Cash payments	(4)
Restructuring reserve. ending balance	$ 0	$ 1

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.

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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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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.

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