Shareholders' Equity - Narrative (Details)		1 Months Ended	12 Months Ended
	Jan. 01, 2017 shares	Nov. 30, 2009 shares	Dec. 31, 2023 USD ($) director vote $ / shares shares	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) $ / shares shares	Aug. 02, 2013 USD ($)
Shareholders' equity, other disclosures
Gross proceeds			$ 0	$ 0	$ 1,110,000,000
Series A Common Shares
Shareholders' equity, other disclosures
Number of votes | vote			10
Number of directors entitled to elect shares | director			8
Common Shares
Shareholders' equity, other disclosures
Number of votes | vote			1
Number of directors entitled to elect shares | director			4
Share repurchases
Repurchase authorization						$ 250,000,000
Repurchase authorization, maximum dollar value			$ 132,000,000
Common Shares | Share Conversion
Shareholders' equity, other disclosures
Shares reserved (in shares) | shares			7,518,000
Common Shares | Tax-Deferred Savings Plan
Shareholders' equity, other disclosures
Shares reserved (in shares) | shares			941,000
UScellular Common Shares | UScellular
Share repurchases
Repurchase authorization, additional number of shares per year (in shares) | shares		1,300,000
Repurchase authorization, cumulative shares authorized (in shares) | shares			1,927,000
UScellular Common Shares | UScellular | Maximum
Share repurchases
Repurchase authorization, additional number of shares per year (in shares) | shares	1,300,000
UScellular Common Shares | UScellular | Minimum
Share repurchases
Repurchase authorization, additional number of shares per year (in shares) | shares	0
Series UU Preferred Shares
Shareholders' equity, other disclosures
Shares issued | shares					16,800
Interest rate			6.625%		6.625%
Shares issued (price per share) | $ / shares					$ 25,000
Gross proceeds					$ 420,000,000
Depositary shares					16,800,000
Net cash proceeds					406,000,000
Issuance costs					$ 14,000,000
Liquidation preference per share (in dollars per share)			$ 25,000
Redemption price per Preferred Share | $ / shares			$ 25,000
Common Shares issued upon conversion | shares			2,773.2
Series UU Preferred Shares | Redemption price after credit rating downgrade
Shareholders' equity, other disclosures
Redemption price per Preferred Share | $ / shares			$ 25,500
Series UU Preferred Shares | Redemption price after change in control
Shareholders' equity, other disclosures
Redemption price per Preferred Share | $ / shares			$ 25,000
Series VV Preferred Shares
Shareholders' equity, other disclosures
Shares issued | shares					27,600
Interest rate			6.00%		6.00%
Shares issued (price per share) | $ / shares					$ 25,000
Gross proceeds					$ 690,000,000
Depositary shares					27,600,000
Net cash proceeds					668,000,000
Issuance costs					$ 22,000,000
Liquidation preference per share (in dollars per share)			$ 25,000
Redemption price per Preferred Share | $ / shares			$ 25,000
Common Shares issued upon conversion | shares			2,584
Series VV Preferred Shares | Redemption price after credit rating downgrade
Shareholders' equity, other disclosures
Redemption price per Preferred Share | $ / shares			$ 25,500
Series VV Preferred Shares | Redemption price after change in control
Shareholders' equity, other disclosures
Redemption price per Preferred Share | $ / shares			$ 25,000