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
Cumulative effect of accounting change	$ 176				$ 175	$ 175	$ 1
Beginning balance at Dec. 31, 2017	3,687	$ 88	$ 1,552	$ (120)	2,157	3,677	10
Net income attributable to U.S. Cellular shareholders	45				45	45
Incentive and compensation plans	2			4	(2)	2
Stock-based compensation awards	8		8			8
Ending balance at Mar. 31, 2018	3,918	88	1,560	(116)	2,375	3,907	11
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