Basis of Presentation - Shared Services Arrangement (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019 USD ($)
Long-term Purchase Commitment [Line Items]
Shares services arrangement, commitment amount	$ 1,300
Shared services arrangement, period	7 years
Shared Services Arrangement with HCL Technologies | Employee Transfers
Long-term Purchase Commitment [Line Items]
Restructuring and related cost incurred	$ 30