Investments - Investments - Mortgage Loans by Region and Property Type (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, after Allowance for Credit Loss	$ 6,047	$ 6,000
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 6,083	$ 6,036
Percent of Total	100.00%	100.00%
Financing Receivable, Allowance for Credit Loss	$ (36)	$ (36)	$ (31)	$ (29)
Financing Receivable, after Allowance for Credit Loss	6,047	6,000
Commercial Loan [Member] | Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 2,266	$ 2,217
Percent of Total	37.30%	36.70%
Commercial Loan [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 2,287	$ 2,247
Percent of Total	37.60%	37.20%
Commercial Loan [Member] | Office
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 585	$ 585
Percent of Total	9.60%	9.70%
Commercial Loan [Member] | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 945	$ 947
Percent of Total	15.50%	15.70%
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] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	100.00%	100.00%
Commercial Loan [Member] | East North Central [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 337	$ 317
Commercial Loan [Member] | East North Central [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	5.60%	5.30%
Commercial Loan [Member] | Middle Atlantic [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 315	$ 316
Commercial Loan [Member] | Middle Atlantic [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	5.20%	5.20%
Commercial Loan [Member] | Mountain [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 706	$ 707
Commercial Loan [Member] | Mountain [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	11.60%	11.70%
Commercial Loan [Member] | New England [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 354	$ 395
Commercial Loan [Member] | New England [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	5.80%	6.50%
Commercial Loan [Member] | Pacific [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 1,279	$ 1,299
Commercial Loan [Member] | Pacific [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	21.00%	21.50%
Commercial Loan [Member] | South Atlantic [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 1,732	$ 1,670
Commercial Loan [Member] | South Atlantic [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	28.50%	27.70%
Commercial Loan [Member] | West North Central [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 111	$ 105
Commercial Loan [Member] | West North Central [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	1.80%	1.70%
Commercial Loan [Member] | West South Central [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 432	$ 421
Commercial Loan [Member] | West South Central [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	7.10%	7.00%
Commercial Loan [Member] | Region Others [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 817	$ 806
Commercial Loan [Member] | Region Others [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	13.40%	13.40%