Net Income (Loss) Per Common 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, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net Income (Loss) Per Common Share [Abstract]
Net Income (Loss) Available to Common Stockholders, Basic	$ (81)	$ 42	$ (160)	$ 119
Less: Dividends paid on unvested restricted stock awards	(1)	(1)	(2)	(2)
Total basic and diluted net income (loss) attributable to Frontier common shareholders	$ (82)	$ 41	$ (162)	$ 117
Total weighted average shares and unvested restricted stock awards outstanding - basic (in shares)	1,168,272	1,002,092	1,068,877	1,001,656
Less: Weighted average unvested restricted stock awards (in shares)	(7,065)	(7,445)	(7,233)	(7,263)
Total weighted average shares outstanding - basic (in shares)	1,161,207	994,647	1,061,644	994,393
Net income per share attributable to common shareholders of Frontier (in dollars per share)	$ (0.07)	$ 0.04	$ (0.15)	$ 0.12
Effect of dilutive shares (in shares)		3,208		3,351
Total weighted average shares outstanding - diluted (in shares)	1,161,207	997,855	1,061,644	997,744
Diluted net income (loss) per common share attributable to Frontier common shareholders	$ (0.07)	$ 0.04	$ (0.15)	$ 0.12