Leases - Other Information (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Other information
Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases	$ 12	$ 41
Right-of-use assets obtained in exchange for lease liabilities: Operating leases	$ 11	$ 178
Weighted average remaining lease term (years): Operating leases	5 years 2 months 12 days	5 years 2 months 12 days
Weighted average discount rate: Operating leases	5.40%	5.40%