Investments - Mortgage Loans by Region and Property Type (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, after Allowance for Credit Loss	$ 6,087	$ 6,000
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 6,138	$ 6,036
Percent of Total	100.00%	100.00%
Financing Receivable, Allowance for Credit Loss	$ 51	$ 36	$ 29	$ 38
Financing Receivable, after Allowance for Credit Loss	6,087	6,000
Commercial Loan [Member] | Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 2,363	$ 2,217
Percent of Total	38.50%	36.70%
Commercial Loan [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 2,200	$ 2,247
Percent of Total	35.90%	37.20%
Commercial Loan [Member] | Office
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 578	$ 585
Percent of Total	9.40%	9.70%
Commercial Loan [Member] | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 917	$ 947
Percent of Total	14.90%	15.70%
Commercial Loan [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 80	$ 0
Percent of Total	1.30%	0.00%
Commercial Loan [Member] | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 0	$ 40
Percent of Total	0.00%	0.70%
Commercial Loan [Member] | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	100.00%	100.00%
Commercial Loan [Member] | East North Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 368	$ 317
Commercial Loan [Member] | East North Central | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	6.00%	5.30%
Commercial Loan [Member] | Middle Atlantic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 238	$ 316
Commercial Loan [Member] | Middle Atlantic | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	3.90%	5.20%
Commercial Loan [Member] | Mountain
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 699	$ 707
Commercial Loan [Member] | Mountain | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	11.40%	11.70%
Commercial Loan [Member] | New England
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 351	$ 395
Commercial Loan [Member] | New England | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	5.70%	6.50%
Commercial Loan [Member] | Pacific
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 1,326	$ 1,299
Commercial Loan [Member] | Pacific | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	21.60%	21.50%
Commercial Loan [Member] | South Atlantic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 1,776	$ 1,670
Commercial Loan [Member] | South Atlantic | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	28.90%	27.70%
Commercial Loan [Member] | West North Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 103	$ 105
Commercial Loan [Member] | West North Central | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	1.70%	1.70%
Commercial Loan [Member] | West South Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 445	$ 421
Commercial Loan [Member] | West South Central | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	7.20%	7.00%
Commercial Loan [Member] | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 832	$ 806
Commercial Loan [Member] | Other | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	13.60%	13.40%