Retirement Plans (Narrative) (Details) - USD ($) $ in Millions	4 Months Ended	8 Months Ended	12 Months Ended
	Apr. 30, 2021	Dec. 31, 2021	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Capitalization of pension and OPEB expense	$ 7	$ 15		$ 18
Estimated Pension And OPEB Expense					$ 21
Pension remeasurement gain				(3)	248
OPEB Remeasurement				$ (3)	$ 248
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate (in hundredths)	3.10%	2.90%		5.20%	5.50%	2.90%	2.60%
Rate of return on plan assets (in hundredths)	7.50%	7.50%		7.50%	7.50%
Benefit obligation				$ 0	$ 200
Settlement threshold				180	175
Pension settlement costs					55
Contributions to plans				134	176	$ 42
Pension payments				129
Plan assets		$ 2,655		2,268	2,033	$ 2,655
Accumulated benefit obligation					200
Actuarial gains (loss)	$ 328	30		$ 44	$ 867
Actuarial gain change basis points				30.00%	260.00%
Benefit payments				$ 204	$ 75
Special termination benefits enhancements				$ 44
Pension [Member] | Scenario, Forecast [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of return on plan assets (in hundredths)			7.50%
Pension [Member] | Minimum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amortization period				7 years
Pension [Member] | Maximum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Amortization period				15 years
401(K) Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
401(k) savings plan employer contributions	$ 14	$ 25		$ 37	$ 38
OPEB [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate (in hundredths)	3.30%	3.00%		5.20%	5.50%	3.00%
Contributions to plans				$ 42	$ 46
Plan assets
Increase (decrease) in accumulated benefit obligation for plan amendment						$ 79
Prior service credits deferred in accumulated comprehensive income				45	40
Actuarial gains (loss)	$ 99	$ 37		$ (3)	248
Annual rate of increase in the per-capita cost of covered medical benefits (in hundredths)				6.75%
Annual rate of increase in the per-capita cost of covered medical benefits in 2032 (in hundredths)				4.75%
Benefit payments				$ 53	$ 56
OPEB [Member] | Minimum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate (in hundredths)		3.00%				3.00%
Fixed Income Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target asset allocation				35.00%
Equity Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target asset allocation				65.00%