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Related Parties (Details) - TTX Company [Member] - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Dec. 31, 2020
Related Party Transaction [Line Items]      
Equity Method Investment, Ownership Percentage 36.79%    
Equity Method Investments $ 1,500   $ 1,500
Related Party Transaction, Expenses from Transactions with Related Party 96 $ 96  
Accounts Payable, Related Parties, Current $ 64   $ 59