Pension And Postretirement Benefits (Other Changes Recognized in Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Roll Forward]
Prior service (cost) credit	$ 1,787	$ (34)	$ 2,250
Amortization of prior service credit	(2,028)	(2,020)	(1,841)
Pension Benefits
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Roll Forward]
Balance at beginning of year	416	525	361
Prior service (cost) credit	0	0	250
Amortization of prior service credit	(100)	(109)	(86)
Total recognized in other comprehensive (income) loss	(100)	(109)	164
Balance at end of year	316	416	525
Postretirement Benefits
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Roll Forward]
Balance at beginning of year	6,496	8,408	8,163
Prior service (cost) credit	1,786	0	2,001
Amortization of prior service credit	(1,928)	(1,912)	(1,756)
Total recognized in other comprehensive (income) loss	(142)	(1,912)	245
Balance at end of year	$ 6,354	$ 6,496	$ 8,408