Investments - Problem and Potential Problem Commercial Mortgage Loans (Details) (Mortgage Loans on Real Estate [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Restructured problem loan, pre-modification	$ 31	$ 119
Restructured problem loan, number of contracts	2	1
Restructured problem loan, post-modification	31
Restructured problem loan, required reserves	0	0
Restructured problem loan, number of contracts - post-modification	2	2
Maximum past due days that the mortgage loans are considered current	59 days
Debt service coverage ratio threshold, below which mortgage loans are considered potential problems	1.0
Loan-to-value ratio threshold, above which mortgage loans are considered potential problems	100.00%
Minimum past due days that mortgage loans are considered potential problems	30 days
Maximum past due days that mortgage loans are considered potential problems	60 days
Problem and potential problem mortgage loans	158	215
Modified Loan 1 [Member]
Financing Receivable, Modifications [Line Items]
Restructured problem loan, post-modification		100
Restructured problem loan, amount reclassified to good standing		100
Amount of troubled debt restructures paid down or paid in full	100
Modified Loan 2 [Member]
Financing Receivable, Modifications [Line Items]
Restructured problem loan, post-modification		19
Amount of troubled debt restructures paid down or paid in full	$ 19