Leases - Schedule of Operating Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Lease cost related to lease liabilities	$ 70	$ 66
Variable lease cost	36	41
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for lease cost	59	60
Lease assets obtained in exchange for new lease liabilities	$ 59	$ 167
Weighted average remaining lease term	8 years 10 months 24 days	8 years 2 months 12 days
Weighted average discount rate	3.02%	3.37%