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, 2016	$ 3,645	$ 88	$ 1,522	$ (136)	$ 2,160	$ 3,634	$ 11
Net income attributable to U.S. Cellular shareholders	26				26	26
Net income attributable to noncontrolling interests classified as equity	1						1
Incentive and compensation plans	3			4	(1)	3
Stock-based compensation awards	7		7			7
Ending balance at Mar. 31, 2017	3,682	88	1,529	(132)	2,185	3,670	12
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
Cumulative effect of accounting change	$ 176				$ 175	$ 175	$ 1