Segment Information: Reconciliation of Segment Income to Consolidated Net (Loss) Income (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment income	$ 24.8		$ (422.9)		$ 38.9	$ (2,804.2)
Depreciation and amortization	(219.9)		(276.0)		(452.5)	(547.5)
Goodwill impairment	0.0		(373.3)		0.0	(2,712.3)
Restructuring and other charges	(5.6)		(6.9)		(12.0)	(22.0)
Other unassigned operating expenses	(1,160.5)		(1,709.4)		(2,347.3)	(5,411.3)
Other income (expense), net	1.7		(9.2)		7.4	(10.2)
Reorganization items, net	(114.4)		(85.4)		(154.9)	(190.3)
Interest expense	(66.0)		(80.8)		(139.1)	(172.7)
Income tax (expense) benefit	(8.5)		54.2		(16.3)	323.0
Net loss	(162.4)	$ (101.6)	(544.1)	$ (2,310.3)	(264.0)	(2,854.4)
Minimum Purchase Commitment Penalty	0.8		30.3		1.2	58.9
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment income	471.4		507.5		948.7	1,011.6
Other unassigned operating expenses	(713.9)		(779.0)		(1,437.5)	(1,595.5)
Corporate, Non-Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other unassigned operating expenses	(52.8)		(105.3)		(108.2)	(196.3)
Leaseback of Telecommunications Network Assets
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Straight-line expense under contractual arrangement with Uniti	$ (168.3)		$ (168.9)		$ (337.1)	$ (337.7)