Employee Retirement Benefits - Net Periodic Income Cost Recognizedf for OCI (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Amortization of unrecognized losses, after Tax	$ 1,000,000	$ 7,000,000	$ 5,000,000
Tax effects on components of net periodic income (cost) recognized in OCI [Abstract]
Amortization of unrecognized losses, Tax	0	(2,000,000)	(1,000,000)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service benefit, after tax	1,000,000	(1,000,000)	0
Net gains (losses), after tax	23,000,000	(139,000,000)	95,000,000
Amortization of unrecognized losses, after Tax	0	7,000,000	6,000,000
Other Comprehensive (Income) Loss Total	24,000,000	(133,000,000)	101,000,000
Tax effects on components of net periodic income (cost) recognized in OCI [Abstract]
Prior service benefit, tax	0	0
Net gains (losses), tax	$ 7,000,000	(43,000,000)	29,000,000
Amortization of unrecognized losses, Tax		$ 2,000,000	$ 2,000,000