Nature of Operations, Basis of Presentation and Summary of Significant Accounting Policies - Summary of Amortization Basis and Expected Amortization Period by Reportable Segment (Details)	12 Months Ended
	Dec. 31, 2023
Annuities | Minimum
Product Information [Line Items]
Traditional contract acquisition cost amortization period	30 years
Annuities | Maximum
Product Information [Line Items]
Traditional contract acquisition cost amortization period	40 years
Life Insurance
Product Information [Line Items]
Traditional contract acquisition cost amortization period	60 years
Group Protection
Product Information [Line Items]
Traditional contract acquisition cost amortization period	4 years
Retirement Plan Services | Minimum
Product Information [Line Items]
Traditional contract acquisition cost amortization period	40 years
Retirement Plan Services | Maximum
Product Information [Line Items]
Traditional contract acquisition cost amortization period	50 years