Acquisitions, Divestitures and Exchanges, acquisitions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Acquisitions, divestitures and exchanges
Total winning bid	338.3usm_FccLicenseAuctionTotalWinningBid
Auction 97
Acquisitions, divestitures and exchanges
Description of acquired entity	An FCC auction of AWS-3 spectrum licenses, referred to as Auction 97, ended in January 2015. U.S. Cellular participated in Auction 97 indirectly through its limited partnership interest in Advantage Spectrum L.P. (“Advantage Spectrum”). Advantage Spectrum was the provisional winning bidder of 124 licenses for an aggregate winning bid of $338.3 million, after its designated entity discount of 25%. Advantage Spectrum’s bid amount, less the initial deposit amount of $60.0 million paid in 2014, was paid to the FCC in March 2015. These licenses are expected to be granted by the FCC during 2015. See Note 9 — Variable Interest Entities (VIEs) for additional information.
License Acquisitions \| Auction 97
Acquisitions, divestitures and exchanges
Federal Communications Commission deposit		60.0
Total winning bid	338.3
Designated entity auction discount	25.00%
Licenses won	124

Acquisitions, divestitures and exchanges

An FCC auction of AWS-3 spectrum licenses, referred to as Auction 97, ended in January 2015. U.S. Cellular participated in Auction 97 indirectly through its limited partnership interest in Advantage Spectrum L.P. (“Advantage Spectrum”). Advantage Spectrum was the provisional winning bidder of 124 licenses for an aggregate winning bid of $338.3 million, after its designated entity discount of 25%. Advantage Spectrum’s bid amount, less the initial deposit amount of $60.0 million paid in 2014, was paid to the FCC in March 2015. These licenses are expected to be granted by the FCC during 2015. See Note 9 — Variable Interest Entities (VIEs) for additional information.

Acquisitions, divestitures and exchanges

Total winning bid

338.3

Licenses won

124