Business, Basis of Presentation and Significant Accounting Policies - Business and Investments (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) Rate shares
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Common stock, shares issued | shares	55,000
Rate required of collateral as a percent of market value of loans securities | Rate	102.00%
Impairment, Long-Lived Asset, Held-for-Use | $	$ 32
Commercial portfolio segment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing receivable, threshold period past due	60 days
Financing receivable, threshold past due, nonaccrual	90 days