Shares and Stockholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2015
Deferred compensation plan mark to market adjustment	$ (7)	$ 4
Common stock warrant [Member]
Outstanding warrant to purchase common stock (in shares)	598,935
Exercise price of warrant (in dollars per share)	$ 9.91
Warrant expiration date LNC deferred compensation plans	Jul. 10, 2019