INCOME TAXES - Federal Tax Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of federal income taxes at the applicable statutory rate to the recorded provision from continuing operations
Federal statutory rate	21.00%	21.00%	21.00%
Adjustments:
Valuation allowance	(6.10%)	(237.10%)	0.70%
State income taxes, net of federal tax benefit	4.00%	56.60%	(8.80%)
Net operating loss carryback	1.90%	0.00%	0.00%
Federal tax credits	1.70%	(684.60%)	(19.90%)
Noncontrolling interest	0.70%	(138.90%)	(0.30%)
Changes in unrecognized tax benefits	(0.20%)	72.20%	0.00%
Effect of consolidated VIEs	(0.10%)	46.30%	1.60%
Stock-based compensation	(0.10%)	(15.90%)	0.50%
Spectrum sales	0.00%	(386.70%)	(5.80%)
Nondeductible items	0.00%	192.70%	0.40%
Capital loss carryback	0.00%	(26.00%)	0.00%
Federal tax reform	0.00%	0.00%	(1.40%)
Other	0.10%	(3.00%)	0.30%
Effective income tax rate	22.90%	(1103.40%)	(11.70%)
Increase (decrease) in valuation allowance	$ 192	$ 16
CARES Act benefit	61
Investment tax credits	42	57	$ 58
Noncontrolling interest	23	12
Change in unrecognized tax benefits	$ 5	4
Gain from sale of broadcast spectrum		34
Addition related to regulatory costs, executive compensation and other not tax-deductible expenses		17
Capital loss carryback		$ 2
Federal tax reform			$ 4

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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