Summary Of Significant Accounting Policies (Narrative) (Details) $ in Millions		3 Months Ended		6 Months Ended
	Jul. 10, 2017 shares	Jun. 30, 2017 USD ($) shares	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) segment shares	Jun. 30, 2016 USD ($)	Jul. 09, 2017 shares	Dec. 31, 2016 shares
Number of reportable segments | segment				1
Common Stock, Shares Authorized		175,000,000		175,000,000			175,000,000
Common stock, shares issued (in shares)		79,532,000		79,532,000			79,532,000
Common stock, shares outstanding (in shares)		78,517,000		78,517,000			78,170,000
Customer surcharges | $		$ 55	$ 62	$ 108	$ 101
Subsequent Event [Member]
Stockholders' Equity, Reverse Stock Split	On July 10, 2017, we effected a one for fifteen reverse stock split of our common stock. The reverse stock split reduced the number of common shares issued (which includes outstanding shares and treasury shares) from approximately 1,193,000,000 shares to 80,000,000 shares, and reduced shares outstanding from 1,178,000,000 shares to 79,000,000 shares. In addition, and at the same time, the total number of shares of common stock that Frontier is authorized to issue changed from 1,750,000,000 shares to 175,000,000 shares. There was no change in the par value of the common stock, and no fractional shares were issued. All share and per share amounts in the financial statements and footnotes have been retroactively adjusted for all periods presented to give effect to the reverse stock split. As a result of our reverse stock split the conversion rates of our Series A Preferred Stock were proportionately adjusted
Common Stock, Shares Authorized	175,000,000					1,750,000,000
Common stock, shares issued (in shares)	80,000,000					1,193,000,000
Common stock, shares outstanding (in shares)	79,000,000					1,178,000,000
Reverse Stock Split, Fractional Shares Issued	0