Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Series A Common and Common shares	Additional paid-in capital	Treasury shares	Retained earnings	Total U.S. Cellular shareholders' equity	Noncontrolling interests
Beginning balance at Dec. 31, 2018	$ 4,067	$ 88	$ 1,590	$ (65)	$ 2,444	$ 4,057	$ 10
Net income attributable to U.S. Cellular shareholders	54				54	54
Net income attributable to noncontrolling interests classified as equity	4					0	4
Incentive and compensation plans	1			2	(1)	1
Stock-based compensation awards	9		9			9
Distributions to noncontrolling interests	(1)					0	(1)
Ending balance at Mar. 31, 2019	4,134	88	1,599	(63)	2,497	4,121	13
Beginning balance at Dec. 31, 2019	4,210	88	1,629	(70)	2,550	4,197	13
Net income attributable to U.S. Cellular shareholders	71				71	71
Repurchase of Common Shares	(23)			(23)		(23)
Incentive and compensation plans	0			1	(1)	0
Stock-based compensation awards	7		7			7
Distributions to noncontrolling interests	(1)					0	(1)
Ending balance at Mar. 31, 2020	$ 4,264	$ 88	$ 1,636	$ (92)	$ 2,620	$ 4,252	$ 12