Leases - Schedule of Operating Leases (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Leases [Abstract]
Lease cost	$ 18
Variable lease cost	13
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for leases	16
Lease assets obtained in exchange for new lease liabilities	$ 129
Weighted average remaining lease term	8 years 9 months 18 days
Weighted average discount rate	3.43%