Long-Term Investments (Schedule Of Pre-Tax Income And Income Tax Effects Related To Investments In Leveraged Leases) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Long-term Investments [Abstract]
Pre-Tax Income (Loss) from Leases	$ 18	$ (39)	$ 17
Income Tax Expense (Benefit) on Income from Leases	$ 2	$ (22)	$ 6