Leases - Schedule of Operating Leases (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Leases [Abstract]
Lease cost	$ 16	$ 50
Variable lease cost	9	32
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for leases	14	45
Lease assets obtained in exchange for new lease liabilities	$ 14	$ 166
Weighted average remaining lease term	8 years 3 months 18 days	8 years 3 months 18 days
Weighted average discount rate	3.36%	3.36%