Investments Investments (Allowance for Credit Loss Roll Forward) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Balance End of Period	$ 33
Fixed Maturities [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Balance Beginning of Period	0
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	33
Financing Receivable, Allowance for Credit Loss, Balance End of Period	33
Fixed Maturities [Member] | Corporate Debt Securities [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Balance Beginning of Period	0
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	26
Financing Receivable, Allowance for Credit Loss, Balance End of Period	26
Fixed Maturities [Member] | Debt Security, Government, Non-US [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Balance Beginning of Period	0
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase	7
Financing Receivable, Allowance for Credit Loss, Balance End of Period	$ 7