Retirement and Other Benefit Plans - Schedule of Fair Values of Pension Plan Assets by Asset Class and Fair Value Hierarchy Level (Detail) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	$ 1,238	$ 1,177
Quoted Prices In Active Markets For Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	1,238	1,177
Mid-sized to Large Cap
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	359	307
Mid-sized to Large Cap | Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	359	307
Small Cap, International and Emerging Growth Funds
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	361	320
Small Cap, International and Emerging Growth Funds | Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	361	320
Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	271	319
Debt Securities | Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	271	319
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	130	137
Real Estate | Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	130	137
Private infrastructure
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	96	90
Private infrastructure | Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	96	90
Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	21	4
Cash Equivalents | Quoted Prices In Active Markets For Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	0	0
Cash Equivalents | Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Fair values of pension plan assets	$ 21	$ 4