Severance and Exit Costs (Schedule of Severance and Exit Costs Liability) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2014		Dec. 31, 2013		Mar. 31, 2015		Mar. 31, 2013		Jul. 10, 2013		Dec. 31, 2012
Successor [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning	$ 1,138		$ 1,176		$ 971
Severance costs, beginning	225		54		197
Restructuring charges	56		328		263
Severance costs	14	[1]	219	[2]	253	[3]
Restructuring reserve, settled with cash	(223)		(366)		(780)
Payments for postemployment benefits	(42)		(48)		(331)
Restructuring reserve, end	971		1,138		454
Severance costs, end	197		225		119
Successor [Member] | Lease [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning	764		933	[4]	650
Restructuring charges excluding US Cellular gain					13
Restructuring charges	11	[5]	56	[6]	(28)	[7]
Restructuring reserved settled with cash and other adjustments	(125)		(225)		(331)
Restructuring reserve, end	650		764		291
Successor [Member] | Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning	149		189		124
Restructuring charges	31	[8]	53	[9]	38	[10]
Restructuring reserved settled with cash and other adjustments	(56)		(93)		(118)
Restructuring reserve, end	124		149		44
Predecessor [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning							244		244
Severance costs, beginning							11		11
Purchase price adjustments									131
Restructuring charges									687
Severance costs							17	[11]	58	[11]
Restructuring reserve, settled with cash									(53)
Payments for postemployment benefits									(15)
Restructuring reserve, end									1,009
Severance costs, end									54
Predecessor [Member] | Lease [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning							190		190
Purchase price adjustments									131
Restructuring reserved settled with cash and other adjustments									(33)
Restructuring reserve, end									766
Predecessor [Member] | Employee Severance [Member]
Restructuring Reserve [Roll Forward]
Purchase price adjustments									0
Predecessor [Member] | Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning							43		43
Purchase price adjustments									0
Restructuring charges									151	[12]
Restructuring reserved settled with cash and other adjustments									(5)
Restructuring reserve, end									189
Cost of Products and Services [Member] | Predecessor [Member] | Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges							7		35
Restructuring Charges [Member] | Predecessor [Member] | Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges									116
Wireline [Member] | Successor [Member]
Restructuring Reserve [Roll Forward]
Severance costs	2		28		35
Wireline [Member] | Successor [Member] | Lease [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges			2		1
Wireline [Member] | Successor [Member] | Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges					5
Wireline [Member] | Predecessor [Member]
Restructuring Reserve [Roll Forward]
Severance costs							3		3
Wireline [Member] | Predecessor [Member] | Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges							3		18
Wireline [Member] | Cost of Products and Services [Member] | Successor [Member] | Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges	4		19
Wireless [Member] | Successor [Member]
Restructuring Reserve [Roll Forward]
Restructuring reserve, accrual adjustment					41
Severance costs	12		191		218
Wireless [Member] | Successor [Member] | Lease [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges			54		12
Wireless [Member] | Successor [Member] | Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges					33
Wireless [Member] | Predecessor [Member]
Restructuring Reserve [Roll Forward]
Severance costs							14		55
Wireless [Member] | Predecessor [Member] | Lease [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges							8	[13]	478	[13]	196
Wireless [Member] | Predecessor [Member] | Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges							4		133
Wireless [Member] | Restructuring Charges [Member] | Successor [Member] | Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring charges	$ 27								$ 34

[1] (5)For the three-month transition period ended March 31, 2014, we recognized costs of $14 million ($12 million Wireless, $2 million Wireline).

[2] (9)For the year ended December 31, 2013, we recognized costs of $219 million ($191 million Wireless, $28 million Wireline).

[3] (2)For the Successor year ended March 31, 2015, we recognized costs of $253 million ($218 million Wireless, $35 million Wireline).

[4] (7)The July 11, 2013 opening balance takes into account purchase price adjustments as it relates to the SoftBank Merger.

[5] (4)For the three-month transition period ended March 31, 2014, we recognized costs of $11 million (solely attributable to Wireless).

[6] (8)For the year ended December 31, 2013, we recognized costs of $56 million ($54 million Wireless, $2 million Wireline).

[7] (1)In addition to the $41 million gain (Wireless only) related to U.S. Cellular recognized, we recognized costs of $13 million ($12 million Wireless and $1 million Wireline) for the year ended March 31, 2015.

[8] (6)For the three-month transition period ended March 31, 2014, $4 million (solely attributable to Wireline) was recognized as "Cost of services" and $27 million (solely attributable to Wireless) was recognized in "Severance and exit costs."

[9] (10)For the year ended December 31, 2013, $19 million (solely attributable to Wireline) was recognized as "Cost of services" and $34 million (solely attributable to Wireless) was recognized in "Severance and exit costs."

[10] (3)For the Successor year ended March 31, 2015, we recognized costs of $38 million ($33 million Wireless, $5 million Wireline).

[11] (12)For the 191-day period ended July 10, 2013, we recognized costs of $58 million ($55 million Wireless, and $3 million was Wireline). For the unaudited three-month period ended March 31, 2013, we recognized net costs of $17 million ($14 million Wireless, and $3 million Wireline).

[12] (13)Of the $151 million ($133 million Wireless; $18 million Wireline) recognized for the 191-day period ended July 10, 2013, $35 million was recognized as "Cost of services" and $116 million was recognized in "Severance and exit costs." For the unaudited three-month period ended March 31, 2013, we recognized $7 million ($4 million Wireless; $3 million Wireline) all as "Cost of services."

[13] (11)For the 191-day period ended July 10, 2013, we recognized net costs of $478 million (solely attributable to our Wireless segment). For the unaudited three-month period ended March 31, 2013, we recognized net costs of $8 million (solely attributable to our Wireless segment).