Property, Plant and Equipment (Summary of Property and Equipment, net) (Parenthetical) (Details) - USD ($) $ in Millions		Mar. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Other property and equipment, net	[1]	$ 1,448	$ 957
CDM [Member]
Property Plant And Equipment [Line Items]
Other property and equipment, net		$ 106	$ 102

[1] $106 million and $102 million related to CDM in 2021 and 2020, respectively.