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		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net Loss Per Share [Abstract]
Net loss attributable to Frontier common shareholders	$ (134)	$ (81)	$ (454)	$ (160)
Less: Dividends paid on unvested restricted stock awards	(1)	(1)	(3)	(2)
Total basic and diluted net loss attributable to Frontier common shareholders	$ (135)	$ (82)	$ (457)	$ (162)
Total weighted average shares and unvested restricted stock awards outstanding - basic (in shares)	1,173,075	1,168,272	1,172,015	1,068,877
Less: Weighted average unvested restricted stock awards (in shares)	(8,903)	(7,065)	(7,903)	(7,233)
Total weighted average shares outstanding - basic (in shares)	1,164,172	1,161,207	1,164,112	1,061,644
Basic net loss per share attributable to Frontier common shareholders	$ (0.12)	$ (0.07)	$ (0.39)	$ (0.15)
Total weighted average shares outstanding - diluted (in shares)	1,164,172	1,161,207	1,164,112	1,061,644
Diluted net loss per share attributable to Frontier common shareholders	$ (0.12)	$ (0.07)	$ (0.39)	$ (0.15)