Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Millions	3 Months Ended		4 Months Ended	5 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Apr. 30, 2021	Sep. 30, 2021	Sep. 30, 2020
Successor [Member]
Revenue	$ 1,576			$ 2,637
Operating expenses:
Network access expenses	177			304
Network related expenses	413			682
Selling, general and administrative expenses	421			690
Depreciation and amortization	273			452
Restructuring costs and other charges	8			19
Total operating expenses	1,292			2,147
Operating income	284			490
Investment and other income (loss), net	(37)			(39)
Interest expense (See note 3)	(90)			(152)
Income (Loss) before income taxes	157			299
Income tax (benefit) expense	31			74
Net income (loss)	$ 126			$ 225
Basic net earnings (loss) per share attributable to Frontier common shareholders	$ 0.52			$ 0.92
Diluted net earnings (loss) per share attributable to Frontier common shareholders	$ 0.51			$ 0.92
Total weighted average shares outstanding - basic	244,403			244,402
Total weighted average shares outstanding - diluted	245,667			245,600
Predecessor [Member]
Revenue		$ 1,726	$ 2,231		$ 5,460
Operating expenses:
Network access expenses		226	264		767
Network related expenses		431	566		1,305
Selling, general and administrative expenses		404	537		1,255
Depreciation and amortization		392	506		1,204
Loss on disposal of Northwest Operations					160
Restructuring costs and other charges		3	7		87
Total operating expenses		1,456	1,880		4,778
Operating income		270	351		682
Investment and other income (loss), net		(14)	1		(29)
Pension settlement costs					(159)
Reorganization items, net		(131)	4,171		(273)
Interest expense (See note 3)		(121)	(118)		(664)
Income (Loss) before income taxes		4	4,405		(443)
Income tax (benefit) expense		(11)	(136)		(91)
Net income (loss)		$ 15	$ 4,541		$ (352)
Basic net earnings (loss) per share attributable to Frontier common shareholders		$ 0.14	$ 43.42		$ (3.37)
Diluted net earnings (loss) per share attributable to Frontier common shareholders		$ 0.14	$ 43.28		$ (3.37)
Total weighted average shares outstanding - basic		104,526	104,584		104,460
Total weighted average shares outstanding - diluted		104,866	104,924		104,460