Statutory Information and Restrictions (Net Gain Loss From Operations, Net Income Loss, Dividends to LNC Holding Company) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statutory Information and Restrictions [Abstract]
U.S. net gain (loss) from operations, after-tax	$ 1,329	$ 1,111	$ 635
U.S. net income (loss)	1,468	1,002	838
U.S. dividends to LNC holding company	$ 974	$ 970	$ 1,175