Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reserve for Doubtful Accounts [Member]
Valuation Allowance [Line Items]
Beginning Balance	$ 8	$ 9
Additions	7	3
Net Deductions and Other	5	4
Ending Balance	10	8
Deferred Tax Valuation Allowance [Member]
Valuation Allowance [Line Items]
Beginning Balance	821	853
Additions	344	64
Net Deductions and Other	53	96
Ending Balance	$ 1,112	$ 821