Severance and Exit Costs (Schedule of Severance and Exit Costs) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Mar. 31, 2015
Restructuring Reserve [Roll Forward]
Restructuring Reserve		$ 285		$ 285		$ 454
Supplemental Unemployment Benefits, Severance Benefits		34		34		119
Restructuring Charges			$ 284	18	$ 311
Severance Costs	[1]	11		18
Payments for Postemployment Benefits				(103)
Restructuring Reserve, Settled with Cash				(187)
Lease [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve		227		227		291
Restructuring Charges	[2]			(2)
Restructuring reserved settled with cash and other adjustments				(62)
Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve		24		24		$ 44
Restructuring reserved settled with cash and other adjustments				(22)
Wireless [Member]
Restructuring Reserve [Roll Forward]
Severance Costs		10
Wireless [Member] | Lease [Member]
Restructuring Reserve [Roll Forward]
Restructuring Charges	[3]	13		18
Wireless [Member] | Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring Charges	[3]	1		2
Wireline [Member]
Restructuring Reserve [Roll Forward]
Severance Costs		1
Other Operating Income (Expense) [Member] | Wireless [Member]
Restructuring Reserve [Roll Forward]
Severance Costs	[1]	16
Restructuring Reserve, Accrual Adjustment				$ 20
Other Operating Income (Expense) [Member] | Wireline [Member]
Restructuring Reserve [Roll Forward]
Severance Costs	[1]	$ 2

[1] For the three and six-month periods ended September 30, 2015, we recognized costs of $11 million ($10 million Wireless, $1 million Wireline), and $18 million ($16 million Wireless, $2 million Wireline), respectively, included in "Other, net" on the consolidated statements of comprehensive loss.

[2] In addition to the $20 million income (Wireless only) related to U.S. Cellular, we recognized costs of $13 million (Wireless only), and $18 million (Wireless only) for the three and six-month periods ended September 30, 2015, respectively, included in "Other, net" on the consolidated statements of comprehensive loss.

[3] For the three and six-month periods ended September 30, 2015, we recognized costs of $1 million (Wireless only), and $2 million (Wireless only), respectively, included in "Other, net" on the consolidated statements of comprehensive loss.