Net Loss Per Share (Calculation Of Net Income (Loss) Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Net Loss Per Share [Abstract]
Net loss attributable to Frontier common shareholders	$ (129)	$ (240)
Less: Dividends paid on unvested restricted stock awards	(1)	(1)
Total basic and diluted net loss attributable to Frontier common shareholders	$ (130)	$ (241)
Total weighted average shares and unvested restricted stock awards outstanding - basic (in shares)	1,173,662	1,170,422
Less: Weighted average unvested restricted stock awards (in shares)	(9,923)	(6,381)
Total weighted average shares outstanding - basic (in shares)	1,163,739	1,164,041
Basic net loss per share attributable to Frontier common shareholders	$ (0.11)	$ (0.21)
Total weighted average shares outstanding - diluted (in shares)	1,163,739	1,164,041
Diluted net loss per share attributable to Frontier common shareholders	$ (0.11)	$ (0.21)