Income Taxes (Schedule Of Unrecognized Tax Benefits Roll Forward) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, beginning of year	$ 92	$ 9	$ 7
Additions based on current year tax positions	46	20	1
Additions based on prior year tax positions	90	68	4
Reductions based on prior year tax positions	0	(5)	(1)
Settlements based on prior year tax positions	(1)	0	(2)
Unrecognized tax benefits, end of year	$ 227	$ 92	$ 9