Employee Postretirement Benefits - Schedule of Assumptions Used to Determine Benefit (Detail)		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		5.66%	5.27%
Rate of compensation increase		4.42%	4.42%
Discount rate	[1]	5.27%		2.77%
Expected long-term return on plan assets		7.05%	7.05%	6.50%
Rate of compensation increase		4.42%	3.79%	3.05%
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		5.69%	5.28%
Rate of compensation increase		4.42%	4.42%
Discount rate	[1]	5.28%		2.84%
Rate of compensation increase		4.42%	3.79%	3.04%
Healthcare cost trend rate
Ultimate rate		4.00%	4.00%	4.00%
Year rate reaches ultimate trend rate		2047	2047	2045
Other Postretirement Benefits [Member] | Immediate Rate [Member]
Healthcare cost trend rate
Immediate rate		7.45%	6.09%
Other Postretirement Benefits [Member] | Initial Rate [Member]
Healthcare cost trend rate
Immediate rate		6.09%	6.39%	5.61%
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		2050	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.