Leases - Schedule of Lease Expense and Other Details Related to Operating Leases (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Operating leases
Operating lease costs	$ 19	$ 58
Variable lease costs	$ 6	16
Supplemental Operating Cash Flows Information
Cash paid for amounts included in the measurement of lease liabilities		61
ROU assets obtained in exchange for new lease obligations		$ 55
Weighted Average Lease terms and discount rates
Remaining lease term	5 years 1 month 24 days	5 years 1 month 24 days
Discount rate	4.09%	4.09%