Leases - Other Information (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Leases [Abstract]
Operating cash flows from operating leases	$ 7	$ 13
Leased assets obtained in exchange for new operating lease liabilities	$ 28	$ 155
Weighted average remaining lease term - operating leases, in years	5 years 8 months 12 days	6 years 1 month 6 days
Weighted average discount rate - operating leases	5.00%	5.00%