Severance and Exit Costs (Schedule of Severance and Exit Costs) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Mar. 31, 2015
Restructuring Reserve [Roll Forward]
Restructuring Reserve		$ 419		$ 419		$ 454
Supplemental Unemployment Benefits, Severance Benefits		184		184		119
Restructuring Charges				227
Severance Costs	[1]	176		194
Payments for Postemployment Benefits				(129)
Restructuring Reserve, Settled with Cash				(262)
Lease [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve		214		214		291
Restructuring Charges	[2]			30
Restructuring reserved settled with cash and other adjustments				(107)
Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve		21		21		$ 44
Restructuring reserved settled with cash and other adjustments				(26)
Wireless [Member]
Restructuring Reserve [Roll Forward]
Severance Costs		156
Wireless [Member] | Lease [Member]
Restructuring Reserve [Roll Forward]
Restructuring Charges	[3]	32		50
Wireless [Member] | Access [Member]
Restructuring Reserve [Roll Forward]
Restructuring Charges	[3]	1		3
Wireline [Member]
Restructuring Reserve [Roll Forward]
Severance Costs		$ 20
Other Operating Income (Expense) [Member] | Wireless [Member]
Restructuring Reserve [Roll Forward]
Severance Costs	[1]			172
Restructuring Reserve, Accrual Adjustment			$ 41	20	$ 41
Other Operating Income (Expense) [Member] | Wireline [Member]
Restructuring Reserve [Roll Forward]
Severance Costs	[1]			$ 22

[1] For the three and nine-month periods ended December 31, 2015, we recognized costs of $176 million ($156 million Wireless, $20 million Wireline), and $194 million ($172 million Wireless, $22 million Wireline), respectively, included in "Severance and Exit Costs" 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 $32 million (Wireless only), and $50 million (Wireless only) for the three and nine-month periods ended December 31, 2015, respectively, included in "Severance and Exit Costs" on the consolidated statements of comprehensive loss.

[3] For the three and nine-month periods ended December 31, 2015, we recognized costs of $1 million (Wireless only), and $3 million (Wireless only), respectively, included in "Severance and Exit Costs" on the consolidated statements of comprehensive loss.