Investments (Credit Quality Indicators For Mortgage Loans) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Mortgage Loans Credit Quality [Line Items]
Principal amount of mortgage loans on real estate	$ 7,086	$ 7,207
Percentage of total mortgage loans on real estate	100.00%	100.00%
Loan-To-Value Ratio, Less Than 65% [Member]
Mortgage Loans Credit Quality [Line Items]
Principal amount of mortgage loans on real estate	5,996	6,026
Percentage of total mortgage loans on real estate	84.60%	83.60%
Debt-service coverage ratio	1.77	1.78
Loan-To-Value Ratio, 65% To 74% [Member]
Mortgage Loans Credit Quality [Line Items]
Principal amount of mortgage loans on real estate	661	744
Percentage of total mortgage loans on real estate	9.30%	10.30%
Debt-service coverage ratio	1.41	1.42
Loan-To-Value Ratio, 75% To 100% [Member]
Mortgage Loans Credit Quality [Line Items]
Principal amount of mortgage loans on real estate	394	402
Percentage of total mortgage loans on real estate	5.60%	5.60%
Debt-service coverage ratio	0.83	0.83
Loan-To-Value Ratio, Greater Than 100% [Member]
Mortgage Loans Credit Quality [Line Items]
Principal amount of mortgage loans on real estate	$ 35	$ 35
Percentage of total mortgage loans on real estate	0.50%	0.50%
Debt-service coverage ratio	0.78	0.78