Pension, Postretirement And Other Employee Benefit Plans - Change in Assumption of Benefit Obligation (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Pension Benefits
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]
100 basis points decrease in the weighted average discount rate	$ 858
100 basis points decrease in the weighted average discount rate	96
100 basis points decrease in the expected long-term rate of return on plan assets	35
Other Postretirement Benefits
Schedule Of Defined Benefit Plans And Defined Contribution Plans Disclosures [Line Items]
100 basis points decrease in the weighted average discount rate	48
100 basis points decrease in the weighted average discount rate	0
100 basis points decrease in the expected long-term rate of return on plan assets	$ 0