Income Taxes (Schedule Of Changes In Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, Balance at beginning of year	$ 202	$ 131
Unrecognized tax benefits, Tax positions taken in prior periods	(7)	36
Unrecognized tax benefits, Tax positions taken in current year	(3)
Unrecognized tax benefits, Accrual of interest related to tax positions taken	16	39
Unrecognized tax benefits, Settlements	(101)
Unrecognized tax benefits, Lapse of statute of limitations		(5)
Unrecognized tax benefits, Foreign currency translation	8	1
Unrecognized tax benefits, Balance at end of year	$ 115	$ 202