Retirement Plans and Other Employee Benefits - Schedule of Assumptions Used in the Defined Benefit Plans (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Qualified pension
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assumptions used calculating benefit obligation, discount rate	5.00%	5.20%	2.95%
Defined benefit plan assumptions used calculating net periodic benefit cost, discount rate	5.20%	2.96%	2.64%
Nonqualified pension
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assumptions used calculating benefit obligation, discount rate	4.90%	5.10%	2.65%
Defined benefit plan assumptions used calculating net periodic benefit cost, discount rate	5.10%	2.65%	2.24%
Other nonqualified pension
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assumptions used calculating benefit obligation, discount rate	4.75%	4.94%	1.99%
Defined benefit plan assumptions used calculating net periodic benefit cost, discount rate	4.94%	1.99%	1.41%
Postretirement benefits | Minimum
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assumptions used calculating benefit obligation, discount rate	4.84%	5.04%	2.43%
Defined benefit plan assumptions used calculating net periodic benefit cost, discount rate	4.88%	2.42%	1.93%
Postretirement benefits | Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assumptions used calculating benefit obligation, discount rate	5.06%	5.25%	3.07%
Defined benefit plan assumptions used calculating net periodic benefit cost, discount rate	5.25%	5.08%	2.81%
Qualified pension/ postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assumptions used calculating net periodic benefit cost, expected long-term rate of return on plan assets	5.15%	2.85%	2.30%
Postretirement benefit (retirees post January 1, 1993)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assumptions used calculating net periodic benefit cost, expected long-term rate of return on plan assets	5.50%	5.95%	5.80%
Postretirement benefit (retirees prior to January 1, 1993)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assumptions used calculating net periodic benefit cost, expected long-term rate of return on plan assets		1.05%	1.00%