Employment Benefit Plans Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Equity securities exceeding 10 percent of plan assets	four	three
Percent of total assets that equity securities exceeding 10 percent of plan assets represent	10.00%	10.00%
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	80.00%	66.00%
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	$ 2,611	$ 2,355	$ 3,170
Pension Benefits | Level 1 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	2,596	2,319
Pension Benefits | Level 2 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	15	36
Pension Benefits | Level 3 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	0
Pension Benefits | Cash and equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	11	32
Pension Benefits | Cash and equivalents | Level 1 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	0
Pension Benefits | Cash and equivalents | Level 2 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	11	32
Pension Benefits | Cash and equivalents | Level 3 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	0
Pension Benefits | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	2,448	2,137
Pension Benefits | Equity Securities | Level 1 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	2,448	2,137
Pension Benefits | Equity Securities | Level 2 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	0
Pension Benefits | Equity Securities | Level 3 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	0
Pension Benefits | Government obligations
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	148	182
Pension Benefits | Government obligations | Level 1 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	148	182
Pension Benefits | Government obligations | Level 2 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	0
Pension Benefits | Government obligations | Level 3 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	0
Pension Benefits | Other fixed maturity securities
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	4	4
Pension Benefits | Other fixed maturity securities | Level 1 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	0
Pension Benefits | Other fixed maturity securities | Level 2 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	4	4
Pension Benefits | Other fixed maturity securities | Level 3 Inputs
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	$ 0	$ 0