Leases - Schedule of Lease Expense and Other Details Related to Operating Leases (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Operating leases
Operating lease costs	$ 20	$ 40
Variable lease costs	$ 4	9
Supplemental Operating Cash Flows Information
Cash paid for amounts included in the measurement of lease liabilities		43
ROU assets obtained in exchange for new lease obligations		$ 47
Weighted Average Lease terms and discount rates
Remaining lease term	5 years 4 months 2 days	5 years 4 months 2 days
Discount rate	4.12%	4.12%