Investments - Mortgage Loans by Region and Property Type (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss			$ 4,215
Financing Receivable, Allowance for Credit Loss			0
Financing Receivable, after Allowance for Credit Loss			4,215
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 5,412	$ 4,531
Percent of Total	100.00%	100.00%
Financing Receivable, Allowance for Credit Loss	$ 29	$ 38	$ 0	$ 1
Financing Receivable, after Allowance for Credit Loss	5,383	4,493
Commercial Loan [Member] | Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 1,931	$ 1,339
Percent of Total	35.70%	29.50%
Commercial Loan [Member] | Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 1,833	$ 1,498
Percent of Total	33.90%	33.10%
Commercial Loan [Member] | Office
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 627	$ 774
Percent of Total	11.60%	17.10%
Commercial Loan [Member] | Retail
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 951	$ 788
Percent of Total	17.60%	17.40%
Commercial Loan [Member] | Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 30	$ 92
Percent of Total	0.50%	2.00%
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%	0.90%
Commercial Loan [Member] | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	100.00%	100.00%
Commercial Loan [Member] | Mortgage loans | Financial Asset, Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 0	$ 0
Commercial Loan [Member] | East North Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 284	$ 290
Commercial Loan [Member] | East North Central | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	5.20%	6.40%
Commercial Loan [Member] | Middle Atlantic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 303	$ 291
Commercial Loan [Member] | Middle Atlantic | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	5.60%	6.40%
Commercial Loan [Member] | Mountain
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 450	$ 254
Commercial Loan [Member] | Mountain | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	8.30%	5.60%
Commercial Loan [Member] | New England
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 393	$ 397
Commercial Loan [Member] | New England | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	7.30%	8.80%
Commercial Loan [Member] | Pacific
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 1,245	$ 1,001
Commercial Loan [Member] | Pacific | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	23.00%	22.10%
Commercial Loan [Member] | South Atlantic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 1,556	$ 1,038
Commercial Loan [Member] | South Atlantic | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	28.80%	22.90%
Commercial Loan [Member] | West North Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 85	$ 44
Commercial Loan [Member] | West North Central | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	1.60%	1.00%
Commercial Loan [Member] | West South Central
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 424	$ 433
Commercial Loan [Member] | West South Central | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	7.80%	9.50%
Commercial Loan [Member] | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 672	$ 783
Commercial Loan [Member] | Other | Mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percent of Total	12.40%	17.30%