Retirement Plans - Schedule of Plan Asset Measured on a Recurring Basis (Details) - Pension Plan - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	$ 3,978	$ 4,068	$ 4,400
Fair Value, Recurring
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	3,978	4,068
Fair Value, Recurring \| Federal government securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	1,471	1,448
Fair Value, Recurring \| Bonds and debentures
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	1,492	1,512
Fair Value, Recurring \| Corporate stock
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	237	226
Fair Value, Recurring \| Venture capital and buyout partnerships
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	$ 413	$ 446
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible Enumeration]	Fair Value Measured at Net Asset Value Per Share	Fair Value Measured at Net Asset Value Per Share
Fair Value, Recurring \| Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	$ 20	$ 26
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible Enumeration]	Fair Value Measured at Net Asset Value Per Share	Fair Value Measured at Net Asset Value Per Share
Fair Value, Recurring \| Collective trust and other funds
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	$ 306	$ 370
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible Enumeration]	Fair Value Measured at Net Asset Value Per Share	Fair Value Measured at Net Asset Value Per Share
Fair Value, Recurring \| Other assets/(liabilities)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	$ 39	$ 40
Fair Value, Recurring \| Fair Value, Inputs, Level 1, Level 2, and Level 3
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	3,200	3,186
Fair Value, Recurring \| Quoted prices in active markets for identical inputs (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	235	220
Fair Value, Recurring \| Quoted prices in active markets for identical inputs (Level 1) \| Federal government securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Fair Value, Recurring \| Quoted prices in active markets for identical inputs (Level 1) \| Bonds and debentures
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Fair Value, Recurring \| Quoted prices in active markets for identical inputs (Level 1) \| Corporate stock
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	235	220
Fair Value, Recurring \| Significant other inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	2,965	2,966
Fair Value, Recurring \| Significant other inputs (Level 2) \| Federal government securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	1,471	1,448
Fair Value, Recurring \| Significant other inputs (Level 2) \| Bonds and debentures
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	1,492	1,512
Fair Value, Recurring \| Significant other inputs (Level 2) \| Corporate stock
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	2	6
Fair Value, Recurring \| Significant unobservable inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Fair Value, Recurring \| Significant unobservable inputs (Level 3) \| Federal government securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Fair Value, Recurring \| Significant unobservable inputs (Level 3) \| Bonds and debentures
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Fair Value, Recurring \| Significant unobservable inputs (Level 3) \| Corporate stock
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	0	0
Fair Value, Recurring \| Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	$ 739	$ 842