Retirement Plans (Schedule Of Amounts Recognized In Statement Of Financial Position) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Amounts recognized - noncurrent assets	$ 8	$ 203
Amounts recognized - current liabilities	(30)	(29)
Amounts recognized - noncurrent liabilities	(620)	(493)
Net amounts recognized at end of year	(642)	(319)
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Amounts recognized - noncurrent assets
Amounts recognized - current liabilities	(18)	(20)
Amounts recognized - noncurrent liabilities	(172)	(185)
Net amounts recognized at end of year	$ (190)	$ (205)

Amount of asset (liability), recognized in statement of financial position, for defined benefit pension and other postretirement plans.

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Amount of asset, recognized in statement of financial position, for overfunded defined benefit pension and other postretirement plans.

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Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as current.

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Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as noncurrent.

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