Supplemental Financial Information - Additional Information (Details) - USD ($) $ in Millions			9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Property, Plant and Equipment [Line Items]
Right-of-use asset obtained in exchange for operating lease liability			$ 42	$ 164
Right-of-use asset obtained in exchange for finance lease liability			7
Lease not yet commenced, assumption and judgment, value of underlying asset, amount	$ 45		$ 45
Property, Plant and Equipment
Property, Plant and Equipment [Line Items]
Capital expenditures incurred but not yet paid	$ 48	$ 47