Employee Postretirement Benefits - Schedule of Assumptions Used to Determine Benefit (Detail)		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		5.27%	5.55%
Rate of compensation increase		4.42%	3.79%
Discount rate	[1]		2.77%	2.37%
Expected long-term return on plan assets		7.05%	6.50%	6.70%
Rate of compensation increase		3.79%	3.05%	3.08%
Pension Benefits [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	[1]	5.55%
Pension Benefits [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	[1]	4.19%
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		5.28%	5.53%
Rate of compensation increase		4.42%	3.79%
Discount rate	[1]		2.84%	2.47%
Rate of compensation increase		3.79%	3.04%	3.07%
Healthcare cost trend rate
Ultimate rate		4.00%	4.00%	4.50%
Year rate reaches ultimate trend rate		2047	2045	2038
Other Postretirement Benefits [Member] | Immediate Rate [Member]
Healthcare cost trend rate
Immediate rate		6.09%	6.39%
Other Postretirement Benefits [Member] | Initial Rate [Member]
Healthcare cost trend rate
Immediate rate		6.39%	5.61%	5.74%
Other Postretirement Benefits [Member] | Ultimate Trend Rate Per Actuary [Member]
Healthcare cost trend rate
Ultimate rate		4.00%	4.00%
Year rate reaches ultimate trend rate		2047	2047
Other Postretirement Benefits [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	[1]	6.14%
Other Postretirement Benefits [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	[1]	5.53%

[1] Discount rate range is the result of remeasurements that occurred in 2023.