Fair Value Measurements - U.S. Pension Benefit Plans (Details) - Pension Benefit Plans - UNITED STATES - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	$ 3,273	$ 3,076	$ 4,157
Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	3,273	3,076
Recurring | Total investment securities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	3,232	3,014
Recurring | Equities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	27	48
Recurring | Commingled funds
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	1,709	1,647
Recurring | Government fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	192	159
Recurring | Corporate fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	894	863
Recurring | Short-term investment funds
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	253	186
Recurring | Private assets
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	157	111
Recurring | Accrued income receivable
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	23	45
Recurring | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	18	17
Recurring | Level 1 | Total investment securities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	1,510	1,393
Recurring | Level 1 | Equities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	27	48
Recurring | Level 1 | Commingled funds
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	1,230	1,159
Recurring | Level 1 | Government fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	0	0
Recurring | Level 1 | Corporate fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	0	0
Recurring | Level 1 | Short-term investment funds
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	253	186
Recurring | Level 1 | Private assets
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	0	0
Recurring | Level 2 | Total investment securities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	1,565	1,510
Recurring | Level 2 | Equities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	0	0
Recurring | Level 2 | Commingled funds
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	479	488
Recurring | Level 2 | Government fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	192	159
Recurring | Level 2 | Corporate fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	894	863
Recurring | Level 2 | Short-term investment funds
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	0	0
Recurring | Level 2 | Private assets
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	0	0
Recurring | Level 3 | Total investment securities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	157	111
Recurring | Level 3 | Equities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	0	0
Recurring | Level 3 | Commingled funds
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	0	0
Recurring | Level 3 | Government fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	0	0
Recurring | Level 3 | Corporate fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	0	0
Recurring | Level 3 | Short-term investment funds
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	0	0
Recurring | Level 3 | Private assets
Defined Benefit Plan Disclosure [Line Items]
Fair value plan assets	$ 157	$ 111