Investments (Age Analysis of Past Due Recorded Investments) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Document Period End Date	Jun. 30, 2020
Financing Receivable, Past Due	$ 87	$ 0
Financing Receivable, Not Past Due	5,953	5,727
Loans Receivable, Gross, Commercial, Real Estate	6,040	5,727
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	15	0
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	63	0
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 9	$ 0