Guaranteed Benefit Features (Narrative) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Guaranteed Benefit Features [Abstract]
Percent of permanent life insurance in force	35.00%		35.00%		35.00%
Percent of permanent life insurance sales	30.00%	28.00%	33.00%	27.00%