Lending Activities - Loan Modifications (Details) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) portfolioSegment
Allowance for losses on Mortgage and other loans receivable
Financing Receivable, Number Of Portfolio Segments | portfolioSegment		2
Commercial Mortgage Loans | Extended Maturity
Allowance for losses on Mortgage and other loans receivable
Amortized cost		$ 87
Commercial Mortgage Loans | Extended Maturity | Fortitude RE
Allowance for losses on Mortgage and other loans receivable
Amortized cost		56
Commercial Loans, Other Loans, And Notes Receivable | Extended Maturity
Allowance for losses on Mortgage and other loans receivable
Amortized cost	$ 168	$ 168