Organization and Basis of Presentation (Summarized Balance Sheet Data) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Current Assets	$ 3,498	$ 3,086
Current Liabilities	2,691	3,997
Equity method investment, nonconsolidated investee or group of investees
Schedule of Equity Method Investments [Line Items]
Current Assets	351	374
Non-current assets	5,235	5,260
Current Liabilities	319	414
Non-current liabilities	$ 686	$ 698