Investments (Mortgage Loans - Narrative) (Details) - Mortgage Loans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables purchased from third parties	$ 815	$ 962
Accrued interest receivable	88
Financing receivable, before allowance for credit losses	15,816	$ 15,728
COVID-19 Pandemic financing receivable in nonaccrual status	38
Financing receivables in nonaccrual status, investment income	2
COVID-19 Pandemic Financial Asset Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 38
Minimum | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses by performance status as a percentage of financing receivables, before allowance for credit losses	99.00%	99.00%
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 2,650	$ 2,708
Financing receivables in nonaccrual status with no allowance for credit losses	7
Residential | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 2,584