Leases - Schedule of Lease Expense and Other Details Related to Operating Leases (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Lease costs
Operating lease costs	$ 20
Variable lease costs	4
Supplemental Operating Cash Flows Information
Cash paid for amounts included in the measurement of lease liabilities	22
ROU assets obtained in exchange for new lease obligations	$ 19
Weighted Average Lease terms and discount rates
Remaining lease term	5 years 2 months 23 days
Discount rate	4.15%