Certain Long-Duration Contracts With Guarantees (Guarantees Associated with Variable Life Contracts, by Guarantee Type) (Details) - Variable Life, Variable Universal Life and Universal Life Contracts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Net Amount at Risk by Product and Guarantee [Line Items]
Separate account value	$ 2,907,924	$ 3,022,615
General account value	5,449,616	4,560,768
Net amount at risk	$ 103,714,953	$ 88,749,362
Average attained age of contractholders	54 years	54 years