Company Restructuring - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges	$ 0	$ 13	$ 27	$ 55
Employee costs
Restructuring Cost and Reserve [Line Items]
Cumulative amount incurred to date for active programs	102		102
Exit costs
Restructuring Cost and Reserve [Line Items]
Cumulative amount incurred to date for active programs	$ 10		$ 10