Fair Values of Financial Instruments - Narrative (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maturity of corporate debt with similar credit risk	20 years
US treasury bond maturity	20 years
Discounted cash flow, discount rate	11.19%	11.27%	11.88%
Discounted cash flow sensitivity analysis discount rate rncrease	10000.00%