Postretirement Benefit Plans (Summary of Plan Assets, Benefit Obligation and Funded Status) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure
Fair value of plan assets	$ 296	$ 246
Projected benefit obligation	(613)	(513)
Unfunded status of the plans	(317)	(267)
Amounts recognized in the balance sheet
Other non-current assets	43	34
Accrued and other current liabilities	(16)	(15)
Accrued post-retirement benefit obligations	(344)	(286)
Net amount recognized	(317)	(267)
Accumulated other comprehensive income:
Net actuarial losses	(95)	(56)
Prior service credit	0	3
Total	(95)	(53)
Pension
Defined Benefit Plan Disclosure
Fair value of plan assets	296	246
Projected benefit obligation	(582)	(482)
Unfunded status of the plans	(286)	(236)
Amounts recognized in the balance sheet
Other non-current assets	43	34
Accrued and other current liabilities	(13)	(12)
Accrued post-retirement benefit obligations	(316)	(258)
Net amount recognized	(286)	(236)
Accumulated other comprehensive income:
Net actuarial losses	(88)	(50)
Prior service credit	(2)	(1)
Total	(90)	(51)
Other Benefits
Defined Benefit Plan Disclosure
Fair value of plan assets	0	0
Projected benefit obligation	(31)	(31)	$ (42)
Unfunded status of the plans	(31)	(31)
Amounts recognized in the balance sheet
Other non-current assets	0	0
Accrued and other current liabilities	(3)	(3)
Accrued post-retirement benefit obligations	(28)	(28)
Net amount recognized	(31)	(31)
Accumulated other comprehensive income:
Net actuarial losses	(7)	(6)
Prior service credit	2	4
Total	(5)	(2)
Level 1
Defined Benefit Plan Disclosure
Fair value of plan assets	51	40
Level 2
Defined Benefit Plan Disclosure
Fair value of plan assets	147	135
Level 3
Defined Benefit Plan Disclosure
Fair value of plan assets	26	20	$ 368
NAV Practical Expedient
Defined Benefit Plan Disclosure
Fair value of plan assets	$ 72	$ 51