Restructuring Restructuring Other Related Charges (Details) $ in Millions	12 Months Ended		24 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2018 Employee
Other Related Charges [Abstract]
Other Nonrecurring Expense		$ 7
Share-based Compensation Arrangement by Share-based Payment Award Accelerated Compensation Cost		$ 2
Charges related to voluntary termination program	$ 16
Charges related to voluntary termination program, Number of Positions Eliminated | Employee			358