Restructuring and Other Charges - Schedule of Restructuring and Other Charges by Reportable Segments, Pretax (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges	$ 9	$ 165	$ 155

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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Period Type:	duration