Benefit Plans and Other Postretirement Benefits, Postretirement Health Care Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Postretirement Health Care Benefits [Abstract]
Estimated costs of health plan subsidies - VRP	$ 1,000,000
Estimated cost of other medical benefits - VRP		$ 0
Other Postretirement Benefits Plan [Member]
Postretirement Health Care Benefits [Abstract]
Discount rate for year-end valuation (as a percent)	5.54%	5.80%
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Pre-65	6.50%	6.50%
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Post-65	5.50%	5.50%
Ultimate health care trend assumption rate (as a percent)	4.50%	4.50%
Period until ultimate trend rate is reached (in years)	$ 6	$ 7
Total benefit obligation	$ 26,000,000	$ 26,000,000	$ 34,000,000
Target pension asset allocations (as a percent)	100.00%	100.00%
Other Postretirement Benefits Plan [Member] | Equity securities
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	9.00%	16.00%
Other Postretirement Benefits Plan [Member] | Long-Duration Fixed Income and Long-duration fixed income and interest rate swap securities
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	0.00%	0.00%
Other Postretirement Benefits Plan [Member] | Short-to-intermediate fixed income securities
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	77.00%	71.00%
Other Postretirement Benefits Plan [Member] | Alternative investments
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	13.00%	12.00%
Other Postretirement Benefits Plan [Member] | Cash
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	1.00%	1.00%
Pension Plan [Member]
Postretirement Health Care Benefits [Abstract]
Discount rate for year-end valuation (as a percent)	5.49%	5.80%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase	4.25%	4.25%
Total benefit obligation	$ 425,000,000	$ 414,000,000	$ 545,000,000
Target pension asset allocations (as a percent)	100.00%	100.00%
Pension Plan [Member] | Equity securities
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	31.00%	33.00%
Pension Plan [Member] | Long-Duration Fixed Income and Long-duration fixed income and interest rate swap securities
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	38.00%	38.00%
Pension Plan [Member] | Short-to-intermediate fixed income securities
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	9.00%	9.00%
Pension Plan [Member] | Alternative investments
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	20.00%	18.00%
Pension Plan [Member] | Cash
Postretirement Health Care Benefits [Abstract]
Target pension asset allocations (as a percent)	2.00%	2.00%