Investments - Investments - Mortgage Loans by Region and Property Type (Details) - USD ($) $ in Millions	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, after Allowance for Credit Loss	$ 5,931		$ 5,383
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 5,967		$ 5,412
Percent of Total	100.00%		100.00%
Financing Receivable, Allowance for Credit Loss	$ (36)	$ (36)	$ (29)	$ (26)	$ (24)	$ (38)
Financing Receivable, after Allowance for Credit Loss	5,931		5,383
Commercial Loan [Member] | Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 2,146		$ 1,931
Percent of Total	36.00%		35.70%
Commercial Loan [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 2,222		$ 1,833
Percent of Total	37.20%		33.90%
Commercial Loan [Member] | Office
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 611		$ 627
Percent of Total	10.20%		11.60%
Commercial Loan [Member] | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 948		$ 951
Percent of Total	15.90%		17.60%
Commercial Loan [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 0		$ 30
Percent of Total	0.00%		0.50%
Commercial Loan [Member] | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 40		$ 40
Percent of Total	0.70%		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	$ 313		$ 284
Commercial Loan [Member] | East North Central [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	5.20%		5.20%
Commercial Loan [Member] | Middle Atlantic [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 291		$ 303
Commercial Loan [Member] | Middle Atlantic [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	4.90%		5.60%
Commercial Loan [Member] | Mountain [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 708		$ 450
Commercial Loan [Member] | Mountain [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	11.90%		8.30%
Commercial Loan [Member] | New England [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 419		$ 393
Commercial Loan [Member] | New England [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	7.00%		7.30%
Commercial Loan [Member] | Pacific [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 1,300		$ 1,245
Commercial Loan [Member] | Pacific [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	21.80%		23.00%
Commercial Loan [Member] | South Atlantic [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 1,643		$ 1,556
Commercial Loan [Member] | South Atlantic [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	27.50%		28.80%
Commercial Loan [Member] | West North Central [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 101		$ 85
Commercial Loan [Member] | West North Central [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	1.70%		1.60%
Commercial Loan [Member] | West South Central [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 422		$ 424
Commercial Loan [Member] | West South Central [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	7.10%		7.80%
Commercial Loan [Member] | Region Others [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 770		$ 672
Commercial Loan [Member] | Region Others [Member] | Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	12.90%		12.40%