Leases - Other Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Other information
Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases	$ 13	$ 15
Right-of-use assets obtained in exchange for lease liabilities: Operating leases	$ 8	$ 161
Weighted average remaining lease term (years): Operating leases	5 years 4 months 24 days		5 years 6 months
Weighted average discount rate: Operating leases	5.60%		5.70%