Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Consolidated Statements Of Operations [Abstract]
Revenue	$ 7,155	$ 8,107	$ 8,611
Operating expenses:
Network access expenses	975	1,247	1,441
Network related expenses	1,726	1,810	1,898
Selling, general and administrative expenses	1,648	1,804	1,815
Depreciation and amortization	1,598	1,780	1,954
Goodwill impairment		5,725	641
Loss on disposal of Northwest Operations	162	446
Restructuring costs and other charges	87	168	35
Total operating expenses	6,196	12,980	7,784
Operating income (loss)	959	(4,873)	827
Investment and other income (loss), net	(43)	(37)	13
Pension settlement costs	(159)	(57)	(41)
Gains (Loss) on early extinguishment of debt	(72)	(20)	32
Reorganization items, net	(409)
Interest expense (contractual interest for the year ended December 31, 2020 was $1,456 million)	(762)	(1,535)	(1,536)
Loss before income taxes	(486)	(6,522)	(705)
Income tax benefit	(84)	(611)	(62)
Net loss	(402)	(5,911)	(643)
Less: Dividends on preferred stock			107
Net loss attributable to Frontier common shareholders	$ (402)	$ (5,911)	$ (750)
Basic and diluted net loss per share attributable to Frontier common shareholders	$ (3.85)	$ (56.80)	$ (8.37)
Total weighted average shares outstanding - basic and diluted	104,467	104,065	89,683