Retirement Plans (Projected Benefit Obligation, Fair Values Of Plan Assets And Amounts Recognized In The Balance Sheet) (Details) - USD ($) $ in Millions	4 Months Ended	8 Months Ended	12 Months Ended
	Apr. 30, 2021	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Amounts recognized in the consolidated balance sheet
Pension and other postretirement benefits - current		$ (46)	$ (39)	$ (46)
Pension and other postretirement benefits - noncurrent		(1,672)	(1,044)	(1,672)
Pension [Member]
Change in projected benefit obligation (PBO)
PBO at beginning of the period	$ 3,708	3,418	3,477	3,708
Service cost	32	53	69		$ 95
Interest cost	31	69	106		108
Actuarial (gain) loss	(328)	30	(867)
Benefits paid	(25)	(93)	(75)
Settlements			(200)		(465)
PBO at end of the period	3,418	3,477	2,510	3,477	3,708
Change in plan assets
Fair value of plan assets at beginning of the period	2,507	2,586	2,655	2,507
Actual return on plan assets	72	152	(523)
Employer contribution	32	10	176	42
Settlements			(200)
Benefits paid	(25)	(93)	(75)
Fair value of plan assets at end of the period	2,586	2,655	2,033	2,655	2,507
Funded status	(832)	(822)	(477)	(822)
Amounts recognized in the consolidated balance sheet
Pension and other postretirement benefits - noncurrent	(832)	(822)	(477)	(822)
Accumulated other comprehensive (gain) loss					915
OPEB [Member]
Change in projected benefit obligation (PBO)
PBO at beginning of the period	1,042	941	897	1,042
Service cost	7	11	13		20
Interest cost	9	18	31		33
Plan amendments		(79)	(41)
Plan participants' contributions	4	6	10
Actuarial (gain) loss	(99)	37	(248)
Benefits paid	(22)	(37)	(56)
PBO at end of the period	941	897	606	897	1,042
Change in plan assets
Fair value of plan assets at beginning of the period
Plan participants' contributions	4	6	10
Employer contribution	18	31	46
Benefits paid	(22)	(37)	(56)
Fair value of plan assets at end of the period
Funded status	(941)	(897)	(606)	(897)
Amounts recognized in the consolidated balance sheet
Pension and other postretirement benefits - current	(48)	(46)	(39)	(46)
Pension and other postretirement benefits - noncurrent	(893)	(851)	(567)	(851)
Accumulated other comprehensive (gain) loss		$ (75)	$ (102)	$ (75)	$ 74