Retirement Plans (Schedule Of Amounts In Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	$ 88	$ 125
Net actuarial loss	3,893	4,757
Amounts recognized in accumulated other comprehensive income (pre-tax)	3,981	4,882
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	(1)	0
Net actuarial loss	67	61
Amounts recognized in accumulated other comprehensive income (pre-tax)	$ 66	$ 61