Employee Benefits - Post-Retirement Benefits, Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefits paid, net of participant contributions and direct subsidy receipts	$ 194,000,000
Expected future benefit payment, next twelve months, net of direct subsidies	$ 193,000,000
Ultimate health care cost trend rate	4.50%
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Initial health care cost trend rate	5.40%
Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Initial health care cost trend rate	7.50%
Post-Retirement Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan	$ (1,918,000,000)	$ (1,990,000,000)
Contributions	$ 0	$ 0
Ultimate health care cost trend rate	4.50%	4.50%	4.50%
Post-Retirement Benefit Plans | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Initial health care cost trend rate	5.40%	5.00%
Post-Retirement Benefit Plans | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Initial health care cost trend rate	7.50%	7.20%
Post-Retirement Benefit Plans | Qualified Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Funded (unfunded) status of plan	$ (1,900,000,000)	$ (2,000,000,000)