Supplementary Financial Information - Other Long-Term Assets (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Condensed Financial Information Disclosure [Abstract]
Capitalized Computer Software, Net	$ 158	$ 150
Deferred Costs, Noncurrent	75	84
Product Software, Net	61	40
Capitalized Cloud Computing Implementation Cost, Net	41	40
Other Assets, Miscellaneous, Noncurrent	67	73
Other long-term assets	$ 402	$ 387