Investments - Investments - Commercial Mortgage Loans Credit Quality (Details) $ in Millions	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 4,215
Commercial Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 4,442	$ 4,215
Avg. Debt-Service Coverage Ratio	2.46	2.46
Commercial Loan [Member] | 65% - 80%
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 376
Avg. Debt-Service Coverage Ratio	1.89	1.53
Commercial Loan [Member] | Less than 65%
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 3,839
Avg. Debt-Service Coverage Ratio	2.59	2.56