Fair Value of Assets and Liabilities (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Separate Account assets transferred from Level 2 to Level 1	$ 0	$ 884,000,000
Separate Account Assets Invested In Real Estate	$ 88,000,000	$ 84,000,000
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rates	4.75%	5.00%
Discount Rates	6.00%	6.75%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rates	10.00%	10.00%
Discount Rates	11.00%	11.00%
Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rates	6.07%	6.68%
Discount Rates	6.95%	7.66%