Debt - Additional Information (Details)			12 Months Ended
	May 11, 2023 USD ($)	Sep. 30, 2021 USD ($) extension_option	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	May 19, 2022
Debt Instrument [Line Items]
Long-term debt, par value, gross			$ 1,650,000,000
Repayment of notes			$ 165,612,000	$ 150,000,000	$ 300,000,000
Activity-based common stock ownership percentage			0.041
FHLB stock			$ 22,300,000	14,300,000
Increase in commercial paper			34,000,000
Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 750,000,000
Potential maximum borrowing capacity		$ 1,000,000,000
Number of extension options | extension_option		2
Extension term		1 year
Estimate of Fair Value Measurement | Asset Pledged as Collateral
Debt Instrument [Line Items]
Fair value of pledged assets			$ 1,300,000,000
Junior Subordinated Debentures Due 2056
Debt Instrument [Line Items]
Interest rate			4.25%
Senior Notes
Debt Instrument [Line Items]
Optional redemption, period from issuance date			5 years
Federal Home Loan Bank Borrowings
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 1,000,000,000
Long-term line of credit			138,000,000	$ 23,000,000
Senior Notes Due 2023
Debt Instrument [Line Items]
Long-term debt, par value, gross	$ 170,000,000		$ 0
Long-term debt, term	18 months
Repayment of notes	$ 166,000,000
Interest rate	7.875%		7.875%
Senior Notes Due 2028
Debt Instrument [Line Items]
Long-term debt, par value, gross			$ 550,000,000
Interest rate						4.55%